Method and apparatus for performing sidelink communication by UE in NR V2X

ABSTRACT

Provided are a method for performing sidelink communication by a first apparatus ( 9010 ), and the first apparatus ( 9010 ) supporting the same. The method may include: receiving, from a second apparatus ( 9020 ), restriction information related to the sidelink communication between the first apparatus ( 9010 ) and the second apparatus ( 9020 ); and performing the sidelink communication with the second apparatus ( 9020 ) based on the restriction information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2019/007229, filed on Jun. 14, 2019,which claims the benefit of earlier filing date and right of priority toKorean Application No. 10-2018-0067840, filed on Jun. 14, 2018, thecontents of which are all hereby incorporated by reference herein intheir entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present invention relates to a wireless communication system, andmore particularly, to a method for performing sidelink communication orV2X communication and an apparatus supporting the same.

Related Art

In order to meet the demand for wireless data traffic, which has beenincreasing since the commercialization of a fourth-generation (4G)communication system, efforts are being made to develop an improvedfifth-generation (5G) communication system or pre-5G communicationsystem. For this reason, a 5G communication system or pre-5Gcommunication system is referred to as a beyond-4G-network communicationsystem or post-long-term evolution (LTE) system.

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present invention can be applied. The 5G usage scenariosshown in FIG. 1 are only exemplary, and the technical features of thepresent invention can be applied to other 5G usage scenarios which arenot shown in FIG. 1 .

Referring to FIG. 1 , the three main requirements areas of 5G include(1) enhanced mobile broadband (eMBB) domain, (2) massive machine typecommunication (mMTC) area, and (3) ultra-reliable and low latencycommunications (URLLC) area. Some use cases may require multiple areasfor optimization and, other use cases may only focus on only one keyperformance indicator (KPI). 5G is to support these various use cases ina flexible and reliable way.

eMBB focuses on across-the-board enhancements to the data rate, latency,user density, capacity and coverage of mobile broadband access. The eMBBaims ˜10 Gbps of throughput. eMBB far surpasses basic mobile Internetaccess and covers rich interactive work and media and entertainmentapplications in cloud and/or augmented reality. Data is one of the keydrivers of 5G and may not be able to see dedicated voice services forthe first time in the 5G era. In 5G, the voice is expected to beprocessed as an application simply using the data connection provided bythe communication system. The main reason for the increased volume oftraffic is an increase in the size of the content and an increase in thenumber of applications requiring high data rates. Streaming services(audio and video), interactive video and mobile Internet connectivitywill become more common as more devices connect to the Internet. Many ofthese applications require always-on connectivity to push real-timeinformation and notifications to the user. Cloud storage andapplications are growing rapidly in mobile communication platforms,which can be applied to both work and entertainment. Cloud storage is aspecial use case that drives growth of uplink data rate. 5G is also usedfor remote tasks on the cloud and requires much lower end-to-end delayto maintain a good user experience when the tactile interface is used.In entertainment, for example, cloud games and video streaming areanother key factor that increases the demand for mobile broadbandcapabilities. Entertainment is essential in smartphones and tabletsanywhere, including high mobility environments such as trains, cars andairplanes. Another use case is augmented reality and informationretrieval for entertainment. Here, augmented reality requires very lowlatency and instantaneous data amount.

mMTC is designed to enable communication between devices that arelow-cost, massive in number and battery-driven, intended to supportapplications such as smart metering, logistics, and field and bodysensors. mMTC aims ˜10 years on battery and/or ˜1 million devices/km².mMTC allows seamless integration of embedded sensors in all areas and isone of the most widely used 5G applications. Potentially by 2020, IoTdevices are expected to reach 20.4 billion. Industrial IoT is one of theareas where 5G plays a key role in enabling smart cities, assettracking, smart utilities, agriculture and security infrastructures.

URLLC will make it possible for devices and machines to communicate withultra-reliability, very low latency and high availability, making itideal for vehicular communication, industrial control, factoryautomation, remote surgery, smart grids and public safety applications.URLLC aims ˜1 ms of latency. URLLC includes new services that willchange the industry through links with ultra-reliability/low latency,such as remote control of key infrastructure and self-driving vehicles.The level of reliability and latency is essential for smart gridcontrol, industrial automation, robotics, drones control andcoordination.

Next, a plurality of use cases included in the triangle of FIG. 1 willbe described in more detail.

5G can complement fiber-to-the-home (FTTH) and cable-based broadband (orDOCSIS) as a means of delivering streams rated from hundreds of megabitsper second to gigabits per second. This high speed can be required todeliver TVs with resolutions of 4K or more (6K, 8K and above) as well asvirtual reality (VR) and augmented reality (AR). VR and AR applicationsinclude mostly immersive sporting events. Certain applications mayrequire special network settings. For example, in the case of a VR game,a game company may need to integrate a core server with an edge networkserver of a network operator to minimize delay.

Automotive is expected to become an important new driver for 5G, withmany use cases for mobile communications to vehicles. For example,entertainment for passengers demands high capacity and high mobilebroadband at the same time. This is because future users will continueto expect high-quality connections regardless of their location andspeed. Another use case in the automotive sector is an augmented realitydashboard. The driver can identify an object in the dark on top of whatis being viewed through the front window through the augmented realitydashboard. The augmented reality dashboard displays information thatwill inform the driver about the object's distance and movement. In thefuture, the wireless module enables communication between vehicles,information exchange between the vehicle and the supportinginfrastructure, and information exchange between the vehicle and otherconnected devices (e.g. devices accompanied by a pedestrian). The safetysystem allows the driver to guide the alternative course of action sothat he can drive more safely, thereby reducing the risk of accidents.The next step will be a remotely controlled vehicle or self-drivingvehicle. This requires a very reliable and very fast communicationbetween different self-driving vehicles and between vehicles andinfrastructure. In the future, a self-driving vehicle will perform alldriving activities, and the driver will focus only on traffic that thevehicle itself cannot identify. The technical requirements ofself-driving vehicles require ultra-low latency and high-speedreliability to increase traffic safety to a level not achievable byhumans.

Smart cities and smart homes, which are referred to as smart societies,will be embedded in high density wireless sensor networks. Thedistributed network of intelligent sensors will identify conditions forcost and energy-efficient maintenance of a city or house. A similarsetting can be performed for each home. Temperature sensors, windows andheating controllers, burglar alarms and appliances are all wirelesslyconnected. Many of these sensors typically require low data rate, lowpower and low cost. However, for example, real-time HD video may berequired for certain types of devices for monitoring.

The consumption and distribution of energy, including heat or gas, ishighly dispersed, requiring automated control of distributed sensornetworks. The smart grid interconnects these sensors using digitalinformation and communication technologies to collect and act oninformation. This information can include supplier and consumerbehavior, allowing the smart grid to improve the distribution of fuel,such as electricity, in terms of efficiency, reliability, economy,production sustainability, and automated methods. The smart grid can beviewed as another sensor network with low latency.

The health sector has many applications that can benefit from mobilecommunications. Communication systems can support telemedicine toprovide clinical care in remote locations. This can help to reducebarriers to distance and improve access to health services that are notcontinuously available in distant rural areas. It is also used to savelives in critical care and emergency situations. Mobile communicationbased wireless sensor networks can provide remote monitoring and sensorsfor parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly importantin industrial applications. Wiring costs are high for installation andmaintenance. Thus, the possibility of replacing a cable with a wirelesslink that can be reconfigured is an attractive opportunity in manyindustries. However, achieving this requires that wireless connectionsoperate with similar delay, reliability, and capacity as cables and thattheir management is simplified. Low latency and very low errorprobabilities are new requirements that need to be connected to 5G.

Logistics and freight tracking are important use cases of mobilecommunications that enable tracking of inventory and packages anywhereusing location based information systems. Use cases of logistics andfreight tracking typically require low data rates, but require a largerange and reliable location information.

SUMMARY OF THE DISCLOSURE

Meanwhile, different services typically have different servicerequirements including different level of QoS as well as functionalrequirements. For this reason, when a UE wants to establish a directconnection with other UE for a certain service, it should be able todetermine whether the direct connection between this direct link canfulfil the required service requirement and thus be able to perform asort of admission control for the requested service.

However, current mechanism of device-to-device communication cannotsupport such functionality.

One embodiment provides a method for performing sidelink communicationby a first apparatus. The method may include: receiving, from a secondapparatus (9020), restriction information related to the sidelinkcommunication between the first apparatus (9010) and the secondapparatus (9020); and performing the sidelink communication with thesecond apparatus (9020) based on the restriction information.

Another embodiment provides a first apparatus (9010) performing sidelinkcommunication. The first apparatus (9010) may include: at least onetransceiver; at least one processor; and at least one computer memoryoperably connectable to the at least one processor and storinginstructions that, when executed, cause the at least one processor toperform operations comprising: receiving, from a second apparatus(9020), restriction information related to the sidelink communicationbetween the first apparatus (9010) and the second apparatus (9020); andperforming the sidelink communication with the second apparatus (9020)based on the restriction information.

A sidelink communication can be performed efficiently between apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present invention can be applied.

FIG. 2 shows a vehicle to which an exemplary embodiment of the presentinvention can be applied.

FIG. 3 shows a control block diagram of a vehicle according to anexemplary embodiment of the present invention.

FIG. 4 shows a control block diagram of a self-driving device to whichthe exemplary embodiment of the present invention can be applied.

FIG. 5 shows a structure of an LTE system to which an exemplaryembodiment of the present invention can be applied.

FIG. 6 shows a radio protocol architecture of a user plane to which anexemplary embodiment of the present invention can be applied.

FIG. 7 shows a radio protocol architecture of a control plane to whichan exemplary embodiment of the present invention can be applied.

FIG. 8 shows a structure of an NR system to which an exemplaryembodiment of the present invention can be applied.

FIG. 9 shows a functional division between an NG-RAN and a 5GC to whichan exemplary embodiment of the present invention can be applied.

FIG. 10 shows a structure of a radio frame of an NR to which anexemplary embodiment of the present invention can be applied.

FIG. 11 shows a structure of a slot of an NR frame to which an exemplaryembodiment of the present invention can be applied.

FIG. 12 shows a protocol stack for a sidelink communication to which theexemplary embodiment of the present invention can be applied.

FIG. 13 shows a protocol stack for a sidelink communication to which theexemplary embodiment of the present invention can be applied.

FIG. 14 shows a terminal performing V2X or sidelink communication towhich an exemplary embodiment of the present invention can be applied.

FIG. 15 shows an exemplary configuration of a resource unit to which anexemplary embodiment of the present invention can be applied.

FIG. 16 shows user equipment (UE) operations according to a transmissionmode (TM) being related to sidelink/V2X communication to which anexemplary embodiment of the present invention can be applied.

FIG. 17 shows an example where a transmission resource to which anexemplary embodiment of the present invention can be applied.

FIG. 18 shows a connection establishment procedure according to anembodiment of the present invention.

FIG. 19 shows a connection establishment procedure according to anembodiment of the present invention.

FIG. 20 shows a connection establishment procedure according to anembodiment of the present invention.

FIG. 21 shows a connection establishment procedure according to anembodiment of the present invention.

FIG. 22 shows a connection establishment procedure according to anembodiment of the present invention.

FIG. 23 shows a connection establishment procedure according to anembodiment of the present invention.

FIG. 24 shows a connection establishment procedure according to anembodiment of the present invention.

FIG. 25 shows a method for performing sidelink communication by a firstapparatus (9010) according to an embodiment of the present invention.

FIG. 26 shows a wireless communication apparatus according to anembodiment of the present invention.

FIG. 27 shows a wireless communication device according to an exemplaryembodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In this document, the term “/” and “,” should be interpreted to indicate“and/or.” For instance, the expression “A/B” may mean “A and/or B.”Further, “A, B” may mean “A and/or B.” Further, “A/B/C” may mean “atleast one of A, B, and/or C.” Also, “A, B, C” may mean “at least one ofA, B, and/or C.”

Further, in the document, the term “or” should be interpreted toindicate “and/or.” For instance, the expression “A or B” may comprise 1)only A, 2) only B, and/or 3) both A and B. In other words, the term “or”in this document should be interpreted to indicate “additionally oralternatively.”

Hereinafter, a vehicle to which the exemplary embodiment of the presentinvention can be applied will be described in detail.

FIG. 2 shows a vehicle to which an exemplary embodiment of the presentinvention can be applied.

Referring to FIG. 2 , a vehicle (100) to which the present invention canbe applied is defined as a transport means that runs (or drives) on aroad or rail. The vehicle (100) corresponds to a concept includingautomobiles, trains, and motorcycles. The vehicle (100) may correspondto a concept that includes all of an internal combustion engine (ICE)vehicle being equipped with an engine as its power source, a hybridvehicle being equipped with an engine and an electric motor as its powersource, an electric vehicle being equipped with an electric motor as itspower source, and so on. The vehicle (100) may correspond to apersonally owned vehicle (POV). The vehicle (100) may also correspond toa shared vehicle. And, the vehicle (100) may correspond to an autonomous(or self-driving) vehicle.

FIG. 3 shows a control block diagram of a vehicle according to anexemplary embodiment of the present invention.

Referring to FIG. 3 , the vehicle (100) may include a user interfacedevice (200), an object detection device (210), a communication device(220), a driving maneuver device (230), a main ECU (240), a drivecontrol device (250), a self-driving device (260), a sensor (270), and aposition data generating device (280). The object detection device(210), the communication device (220), the driving maneuver device(230), the main ECU (240), the drive control device (250), theself-driving device (260), the sensor (270), and the position datagenerating device (280) may each generate an electrical signal and maycollectively embody an electrical device exchanging electrical signalsbetween each block.

1) User interface device

The user interface device (200) corresponds to a device being configuredfor a communication between the vehicle (100) and the user. The userinterface device (200) may receive user input and may provideinformation generated from the vehicle (100) to the user. The vehicle(100) may implement a User Interface (UI) or User Experience (UX) viathe user interface device (200). The user interface device (200) mayinclude an input device, an output device, and a user monitoring device.

2) Object detection device

The object detection device (210) may generate information on an objectbeing positioned outside of the vehicle (100). The information on anobject may include at least any one of information on the presence orabsence of an object, position information of the object, information ona distance between the vehicle (100) and the object, and information ona relative velocity between the vehicle (100) and the object. The objectdetection device (210) may detect an object being positioned outside ofthe vehicle (100). The object detection device (210) may include atleast one sensor capable of detecting an object being positioned outsideof the vehicle (100). The object detection device (210) may include atleast any one of a camera, a radar, a lidar, an ultrasonic sensor, andan infrared sensor. The object detection device (210) may provide theobject-related data generated based on a sensing signal, which isgenerated from a sensor, to at least one of the electronic devicesincluded in the vehicle.

2.1) Camera

The camera may generate information on an object being positionedoutside of the vehicle (100) by using an image. The camera may includeat least one lens, at least one image sensor, and at least on processorbeing electrically connected to the at least one image sensor so as toprocess received signals and generating data related to the object basedon the processed signals.

The camera may correspond to at least any one of a mono camera, a stereocamera, and an Around View Monitoring (AVM) camera. The camera mayacquire position information of an object, information on a distancebetween the camera and the object or information on a relative velocitybetween the camera and the object, by using diverse image processingalgorithms. For example, the camera may acquire the information on thedistance and relative velocity between the camera and the object, fromthe acquired image, based on a change in object size in accordance withtime. For example, the camera may acquire the information on thedistance and relative velocity between the camera and the object viapinhole model, road profiling, and so on. For example, the camera mayacquire the information on the distance and relative velocity betweenthe camera and the object from a stereo image, which is acquired fromthe stereo camera, based on disparity information.

In order to capture the exterior of the vehicle, the camera may bemounted at a position of the vehicle from which a field of view (FOV)can be ensured. In order to capture a front area of the vehicle, thecamera may be installed near a front windshield inside the vehicle. Thecamera may be installed near a front bumper or radiator grill. In orderto capture a back area of the vehicle, the camera may be installed neara rear glass inside the vehicle. The camera may be installed near a rearbumper, a trunk, or tail gate. In order to capture a side area of thevehicle, the camera may be installed near at least any one side windowinside the vehicle. Alternatively, the camera may be installed near aside mirror, a fender, or a door.

2.2) Radar

The radar may generate information on an object being positioned outsideof the vehicle (100) by using radio waves. The radar may include a radiowave transmitter, a radio wave receiver, and at least one processorbeing electrically connected to the radio wave transmitter and the radiowave receiver so as to process received signals and generating data onthe object based on the processed signals. The radar may be implementedas a pulse radar or a continuous-wave radar. Herein, the continuous-waveradar may be implemented as a Frequency Modulated Continuous Wave (FMCW)radar or a Frequency Shift Keying (FSK) radar. The radar may detect anobject based on a Time of Flight (TOF) method or a phase-shift method byusing radio waves and may then detect a position of the detected object,and a distance and relative velocity between the radar and the detectedobject. The radar may be adequately installed on the outside of thevehicle in order to detect an object, which is positioned in front ofthe vehicle, behind the vehicle, or at the side of the vehicle.

2.3) Lidar

The lidar may generate information on an object being positioned outsideof the vehicle (100) by using laser light. The lidar may include a lighttransmitter, a light receiver, and at least one processor beingelectrically connected to the light transmitter and the light receiverso as to process received signals and generating data on the objectbased on the processed signals. The lidar may be implemented by using aTime of Flight (TOF) method or a phase-shift method. The lidar may beimplemented as an operational lidar or a non-operational lidar. In casethe lidar is implemented as the operational type, the lidar is rotatedby a motor and may detect any object in the surroundings of the vehicle(100). In case the lidar is implemented as the non-operational type, thelidar may detect objects being located within a predetermined range fromthe vehicle (100) via optical steering. The vehicle (100) may include aplurality of non-operational lidars. The lidar may detect an objectbased on a Time of Flight (TOF) method or a phase-shift method by usinglaser light and may then detect a position of the detected object, and adistance and relative velocity between the lidar and the detectedobject. The lidar may be adequately installed on the outside of thevehicle in order to detect an object, which is positioned in front ofthe vehicle, behind the vehicle, or at the side of the vehicle.

3) Communication device

The communication device (220) may wirelessly exchanges signals with adevice located outside of the vehicle (100). The communication device(220) may exchange signals with an external device through a network ormay directly exchange signals with an external device. An externaldevice may include at least any one of a server, a mobile equipment (ordevice), and another vehicle. For example, the communication device(220) may exchange signals with at least one user equipment (UE). Inorder to perform communication, the communication device (220) mayinclude at least any one of a radio frequency (RF) circuit and an RFdevice that can implement at least one communication protocol. Accordingto the exemplary embodiment of the present invention, the communicationdevice (220) may also use a plurality of communication protocols. Thecommunication device (220) may shift communication protocols inaccordance with its distance from a mobile equipment.

For example, the communication device may exchange signals with anexternal device based on a Cellular V2X (C-V2X) technology. For example,the C-V2X technology may include an LTE-based sidelink communicationand/or an NR-based sidelink communication. Details on the C-V2X will bedescribed later on.

For example, the communication device may exchange signals with anexternal device based on an IEEE 802.11p PHY/MAC layer technology andIEEE 1609 Network/Transport layer technology based Dedicated Short RangeCommunications (DSRC) technology or Wireless Access in VehicularEnvironment (WAVE) specification. The DSRC (or WAVE specification)technology corresponds to a communication standard that has been devisedto provide Intelligent Transport System (ITS) services via short rangededicated communication between on-board units or between a roadsideunit and an on-board unit. The DSRC technology may use a 5.9 GHz bandfrequency and may perform communication having a data transmission rateof 3 Mbps-27 Mbps. The IEEE 802.11p technology may be combined with theIEEE 1609 technology so as to support the DSRC technology (or WAVEspecification).

The communication device according to the present invention may exchangesignals with an external device by using only any one of the C-V2Xtechnology and the DSRC technology. Alternatively, the communicationdevice according to the present invention may exchange signals with anexternal device by using a hybrid technology consisting of the C-V2Xtechnology and the DSRC technology.

4) Driving maneuver device

The driving maneuver device (230) corresponds to a device receiving userinput for driving. In case of a manual mode, the vehicle (100) may beoperated based on signals being provided by the driving maneuver device(230). The driving maneuver device (230) may include a steering inputdevice (e.g., steering wheel), an acceleration input device (e.g.,accelerator pedal), and a brake input device (e.g., brake pedal).

5) Main ECU

The main ECU (240) may control overall operations of at least oneelectronic device being equipped in the vehicle (100).

6) Drive control device

The drive control device (250) corresponds to a device being configuredto electrically control diverse types of vehicle driving devices withinthe vehicle (100). The drive control device (250) may include apowertrain drive control device, a chassis drive control device, adoor/window drive control device, a safety unit drive control device, alamp drive control unit, and a duct drive control device. The powertraindrive control device may include a power source drive control device anda transmission drive control device. The chassis drive control devicemay include a steering drive control device, a brake drive controldevice, and a suspension drive control device. The safety unit drivecontrol device may include a safety belt (or seat belt) drive controldevice for controlling safety belts (or seat belts).

The drive control device (250) includes at least one electronic controldevice (e.g., Electronic Control Unit (ECU)).

The drive control device (250) may control the vehicle driving devicesbased on the signals received from the self-driving device (260). Forexample, the drive control device (250) may control the powertrain, thesteering device, and the brake device based on the signals received fromthe self-driving device (260).

7) Self-driving device

The self-driving device (260) may generate a path for self-driving basedon the acquired data. The self-driving device (260) may generate adriving plan in accordance with the generated path. The self-drivingdevice (260) may generate a signal for controlling movements of thevehicle (100) according the driving place. The self-driving device (260)may provide the generated signals to the drive control device (250).

The self-driving device (260) may implement at least one Advanced DriverAssistance System (ADAS) function. The ADAS may implement at least anyone of an Adaptive Cruise Control (ACC) system, an Autonomous EmergencyBraking (AEB) system, a Forward Collision Warning (FCW) system, a LaneKeeping Assist (LKA) system, a Lane Change Assist (LCA) system, a TargetFollowing Assist (TFA) system, a Blind Spot Detection (BSD) system, anadaptive High Beam Assist (HBA) system, an Auto Parking System (APS), apedestrian (PD) collision warning system, a Traffic Sign Recognition(TSR) system, a Traffic Sign Assist (TSA) system, a Night Vision (NV)system, a Driver Status Monitoring (DSM) system, and a Traffic JamAssist (TJA) system.

The self-driving device (260) may perform a shifting operation from theself-driving mode to the manual driving mode or a shifting operationfrom the manual driving mode or the self-driving mode. For example, theself-driving device (260) may shift the driving mode of the vehicle(100) from the self-driving mode to the manual mode or from the manualmode to the self-driving mode based on the signals received from theuser interface device (200).

8) Sensor

The sensor (270) may sense the vehicle status. The sensor (270) mayinclude at least any one of an inertial measurement unit (IMU) sensor, acollision sensor, a wheel sensor, a speed sensor, an inclination sensor,a weight detection sensor, a heading sensor, a position module, avehicle forward/reverse sensor, a battery sensor, a fuel sensor, a tiresensor, a steering sensor, a temperature sensor, a humidity sensor, anultrasonic sensor, an illuminance sensor, and a pedal position sensor.Meanwhile, the inertial measurement unit (IMU) sensor may include one ormore of an acceleration sensor, a gyro sensor, and a magnetic sensor.

The sensor (270) may generate the vehicle status data based on thesignals generated from at least one of the sensors. The vehicle statusdata may correspond to information being generated based on the datadetected from diverse sensors equipped in the vehicle. The sensor (270)may generate data, such as vehicle stability data, vehicle motion data,vehicle yaw data, vehicle roll data, vehicle pitch data, vehiclecollision data, vehicle direction data, vehicle angle data, vehiclespeed data, vehicle acceleration data, vehicle inclination data, vehicleforward/reverse data, vehicle weight data, battery data, fuel data, tireair pressure data, vehicle indoor temperature data, vehicle indoorhumidity data, steering wheel rotation angle data, vehicle outdoorilluminance data, data on pressure applied to the acceleration pedal,data on pressure applied to the brake pedal, and so on.

9) Position data generating device

The position data generating device (280) may generate position data ofthe vehicle (100). The position data generating device (280) may includeat least any one of a Global Positioning System (GPS) and a DifferentialGlobal Positioning System (DGPS). The position data generating device(280) may generate the position data of the vehicle (100) based onsignals being generated from at least any one of the GPS and the DGPS.According to an exemplary embodiment of the present invention, theposition data generating device (280) may calibrate the position databased on at least any one of the Inertial Measurement Unit (IMU) of thesensor (270) and the camera of the object detection device (210). Theposition data generating device (280) may be referred to as a GlobalNavigation Satellite System (GNSS).

The vehicle (100) may include an internal communication system (290). Aplurality of electronic devices being included in the vehicle (100) mayexchange signals between one another by using the internal communicationsystem (290). Data may be included in the corresponding signals. Theinternal communication system (290) may use at least one communicationprotocol (e.g., CAN, LIN, FlexRay, MOST, Ethernet).

FIG. 4 shows a control block diagram of a self-driving device to whichthe exemplary embodiment of the present invention can be applied.

Referring to FIG. 4 , the self-driving device (260) may include a memory(140), a processor (170), an interface unit (180), and a power supply(190).

The memory (140) is electrically connected to the processor (170). Thememory (140) may store basic (or primary) data on a unit, control datafor controlling operations of a unit, and data being inputted andoutputted. The memory (140) may be configured in the form of hardware asat least any one of ROM, RAM, EPROM, flash drive, and hard drive. Thememory (140) may store diverse data for the overall operations of theself-driving device (260), such as programs for processing orcontrolling the processor (170). The memory (140) may be implemented asa single body with the processor (170). According to the exemplaryembodiment of the present invention, the memory (140) may be classifiedas a sub-structure of the processor (170).

The interface unit (180) may exchange signals with at least oneelectronic device being equipped in the vehicle (100) via wired orwireless connection. The interface unit (180) may exchange signals withat least one of the object detection device (210), the communicationdevice (220), the driving maneuver device (230), the main ECU (240), thedrive control device (250), the sensor (270), and the position datagenerating device (280) via wired or wireless connection. The interfaceunit (180) may be configured of any one of a communication module, aterminal, a pin, a cable, a port, a circuit, an element, and a device.

The power supply (190) may supply power to the self-driving device(260). The power supply (190) may be supplied with power from a powersource (e.g., battery), which is included in the vehicle (100), and thepower may then be supplied to each unit of the self-driving device(260). The power supply (190) may be operated in accordance with acontrol signal, which is provided by the main ECU (240). The powersupply (190) may include a switched-mode power supply (SMPS).

The processor (170) may be electrically connected to the memory (140),the interface unit (180), and the power supply (190) and may exchangesignals to and from one another. The processor (170) may be implementedby using at least one of application specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), processors (FPGAs), controllers, micro-controllers,microprocessors, and electric units performing many other functions.

The processor (170) may be operated by power provided from the powersupply (190). The processor (170) may receive data while being providedwith power from the power supply (190), process data, generate signals,and provide the generated signals.

The processor (170) may receive information from another electronicdevice equipped in the vehicle (100) via the interface unit (180). Theprocessor (170) may provide control signals to another electronic deviceequipped in the vehicle (100) via the interface unit (180).

The self-driving device (260) may include at least one printed circuitboard (PCB). The memory (140), the interface unit (180), the powersupply (190), and the processor (170) may be electrically connected tothe printed circuit board (PCB).

Hereinafter, a communication technology to which an exemplary embodimentof the present invention is to be applied will be described in detail.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features of the presentinvention will not be limited only to this.

FIG. 5 shows a structure of an LTE system to which an exemplaryembodiment of the present invention can be applied. This may also bereferred to as an Evolved-UMTS Terrestrial Radio Access Network(E-UTRAN), or a Long Term Evolution (LTE)/LTE-A system.

Referring to FIG. 5 , the E-UTRAN includes a base station (BS) (20),which provides a control plane and a user plane to a user equipment (UE)(10). The UE (10) may be fixed or mobile and may also be referred to byusing different terms, such as Mobile Station (MS), User Terminal (UT),Subscriber Station (SS), Mobile Terminal (MT), wireless device, and soon. The base station (20) refers to a fixed station that communicatedwith the UE (10) and may also be referred to by using different terms,such as evolved-NodeB (eNB), Base Transceiver System (BTS), Access Point(AP), and so on.

The base stations (20) are interconnected to one another through an X2interface. The base stations (20) are connected to an Evolved PacketCore (EPC) (30) through an S1 interface. More specifically, the basestation (20) are connected to a Mobility Management Entity (MME) throughan S1-MME interface and connected to Serving Gateway (S-GW) through anS1-U interface.

The EPC (30) is configured of an MME, an S-GW, and a Packet DataNetwork-Gateway (P-GW). The MME has UE access information or UEcapability information, and such information may be primarily used in UEmobility management. The S-GW corresponds to a gateway having an E-UTRANas its endpoint. And, the P-GW corresponds to a gateway having a PDN asits endpoint.

Layers of a radio interface protocol between the UE and the network maybe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of an open systeminterconnection (OSI) model, which is well-known in the communicationsystem. Herein, a physical layer belonging to the first layer provides aphysical channel using an Information Transfer Service, and a RadioResource Control (RRC) layer, which is located in the third layer,executes a function of controlling radio resources between the UE andthe network. For this, the RRC layer exchanges RRC messages between theUE and the base station.

FIG. 6 shows a radio protocol architecture of a user plane to which anexemplary embodiment of the present invention can be applied. FIG. 7shows a radio protocol architecture of a control plane to which anexemplary embodiment of the present invention can be applied. The userplane corresponds to a protocol stack for user data transmission, andthe control plane corresponds to a protocol stack for control signaltransmission.

Referring to FIG. 6 and FIG. 7 , a physical (PHY) layer belongs to theL1. A physical (PHY) layer provides an information transfer service to ahigher layer through a physical channel. The PHY layer is connected to amedium access control (MAC) layer. Data is transferred (or transported)between the MAC layer and the PHY layer through a transport channel. Thetransport channel is sorted (or categorized) depending upon how andaccording to which characteristics data is being transferred through theradio interface.

Between different PHY layers, i.e., a PHY layer of a transmitter and aPHY layer of a receiver, data is transferred through the physicalchannel. The physical channel may be modulated by using an orthogonalfrequency division multiplexing (OFDM) scheme and uses time andfrequency as radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRLC SDU. In order to ensure diverse quality of service (QoS) required bya radio bearer (RB), the RLC layer provides three types of operationmodes, i.e., a transparent mode (TM), an unacknowledged mode (UM), andan acknowledged mode (AM). An AM RLC provides error correction throughan automatic repeat request (ARQ).

The radio resource control (RRC) layer is defined only in a controlplane. And, the RRC layer performs a function of controlling logicalchannel, transport channels, and physical channels in relation withconfiguration, re-configuration, and release of radio bearers. The RBrefers to a logical path being provided by the first layer (PHY layer)and the second layer (MAC layer, RLC layer, PDCP layer) in order totransport data between the UE and the network.

Functions of a Packet Data Convergence Protocol (PDCP) in the user planeinclude transfer, header compression, and ciphering of user data.Functions of a Packet Data Convergence Protocol (PDCP) in the controlplane include transfer and ciphering/integrity protection of controlplane data.

The configuration of the RB refers to a process for specifying a radioprotocol layer and channel properties in order to provide a particularservice and for determining respective detailed parameters and operationmethods. The RB may then be classified into two types, i.e., a signalingradio bearer (SRB) and a data radio bearer (DRB). The SRB is used as apath for transmitting an RRC message in the control plane, and the DRBis used as a path for transmitting user data in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in a RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the base station is released.

Downlink transport channels transmitting (or transporting) data from anetwork to a UE include a Broadcast Channel (BCH) transmitting systeminformation and a downlink Shared Channel (SCH) transmitting other usertraffic or control messages. Traffic or control messages of downlinkmulticast or broadcast services may be transmitted via the downlink SCHor may be transmitted via a separate downlink Multicast Channel (MCH).Meanwhile, uplink transport channels transmitting (or transporting) datafrom a UE to a network include a Random Access Channel (RACH)transmitting initial control messages and an uplink Shared Channel (SCH)transmitting other user traffic or control messages.

Logical channels existing at a higher level than the transmissionchannel and being mapped to the transmission channel may include aBroadcast Control Channel (BCCH), a Paging Control Channel (PCCH), aCommon Control Channel (CCCH), a Multicast Control Channel (MCCH), aMulticast Traffic Channel (MTCH), and so on.

A physical channel is configured of a plurality of OFDM symbols in thetime domain and a plurality of sub-carriers in the frequency domain. Onesubframe is configured of a plurality of OFDM symbols in the timedomain. A resource block is configured of a plurality of OFDM symbolsand a plurality of sub-carriers in resource allocation units.Additionally, each subframe may use specific sub-carriers of specificOFDM symbols (e.g., first OFDM symbol) of the corresponding subframe fora Physical Downlink Control Channel (PDCCH), i.e., L1/L2 controlchannels. A Transmission Time Interval (TTI) refers to a unit time of asubframe transmission.

FIG. 8 shows a structure of an NR system to which an exemplaryembodiment of the present invention can be applied.

Referring to FIG. 8 , an NG-RAN may include a gNB and/or eNB providing auser plane and control plane protocol termination to a user. FIG. 8shows a case where the NG-RAN includes only the gNB. The gNB and the eNBare connected to one another via Xn interface. The gNB and the eNB areconnected to one another via 5th Generation (5G) Core Network (5GC) andNG interface. More specifically, the gNB and the eNB are connected to anaccess and mobility management function (AMF) via NG-C interface, andthe gNB and the eNB are connected to a user plane function (UPF) viaNG-U interface.

FIG. 9 shows a functional division between an NG-RAN and a 5GC to whichan exemplary embodiment of the present invention can be applied.

Referring to FIG. 9 , the gNB may provide functions, such as Inter CellRadio Resource Management (RRM), Radio Bearer (RB) control, ConnectionMobility Control, Radio Admission Control, Measurement Configuration &Provision, Dynamic Resource Allocation, and so on. An AMF may providefunctions, such as NAS security, Idle state mobility processing, and soon. A UPF may provide functions, such as Mobility Anchoring, PDUprocessing, and so on. A Session Management Function (SMF) may providefunctions, such as user equipment (UE) IP address allocation, PDUsession control, and so on.

FIG. 10 shows a structure of a radio frame of an NR to which anexemplary embodiment of the present invention can be applied.

Referring to FIG. 10 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined in accordance with subcarrier spacing (SCS).Each slot may include 12 or 14 OFDM(A) symbols according to a cyclicprefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and an SC-FDMAsymbol (or DFT-s-OFDM symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)), a number slots per frame (N^(frame,u) _(slot)),and a number of slots per subframe (N^(subframe,u) _(slot)) inaccordance with an SCS configuration (μ), in a case where a normal CP isused.

TABLE 1 SCS (15 * 2u) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 14 20 2 60KHz (u = 2) 14 40 4 120 KHz (u = 3) 14 80 8 240 KHz (u = 4) 14 160 16

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe in accordance withthe SCS, in a case where an extended CP is used.

TABLE 2 SCS (15 * 2{circumflex over ( )}u) N^(slot) _(symb) N^(frame,u)_(slot) N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

FIG. 11 shows a structure of a slot of an NR frame to which an exemplaryembodiment of the present invention can be applied.

Referring to FIG. 11 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (P)RBs in thefrequency domain, and the BWP may correspond to one numerology (e.g.,SCS, CP length, and so on). A carrier may include a maximum of N numberBWPs (e.g., 5 BWPs). Data communication may be performed via anactivated BWP. Each element may be referred to as a Resource Element(RE) within a resource grid and one complex symbol may be mapped to eachelement.

Hereinafter, V2X or sidelink communication will be described in detail.

FIG. 12 shows a protocol stack for a sidelink communication to which theexemplary embodiment of the present invention can be applied. Morespecifically, (a) of FIG. 12 represents a user plane protocol stack ofLTE, and (b) of FIG. 12 represents a control plane protocol stack ofLTE.

FIG. 13 shows a protocol stack for a sidelink communication to which theexemplary embodiment of the present invention can be applied. Morespecifically, (a) of FIG. 13 represents a user plane protocol stack ofNR, and (b) of FIG. 13 represents a control plane protocol stack of NR.

Hereinafter, Sidelink Synchronization Signal (SLSS) and synchronizationinformation will be described in detail.

SLSS corresponds to a sidelink specific sequence, which may include aPrimary Sidelink Synchronization Signal (PSSS) and a Secondary SidelinkSynchronization Signal (SSSS). The PSSS may also be referred to as aSidelink Primary Synchronization Signal (S-PSS), and the SSSS may alsobe referred to as a Sidelink Secondary Synchronization Signal (S-SSS).

A Physical Sidelink Broadcast Channel (PSBCH) may correspond to a(broadcast) channel through which basic (system) information that shouldfirst be known by the user equipment (UE) before transmitting andreceiving sidelink signals. For example, the basic information maycorrespond to information related to SLSS, a Duplex mode (DM), TDD UL/DLconfiguration, information related to a resource pool, application typesrelated to SLSS, a subframe offset, broadcast information, and so on.

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., a sidelink SS/PSBCH block, hereinafter referred to as S-SSB). TheS-SSB may have the same numerology (i.e., SCS and CP length) as aPhysical Sidelink Control Channel (PSCCH)/Physical Sidelink SharedChannel (PSSCH) within the carrier, and a transmission bandwidth mayexist within a (pre-)configured SL BWP. And, a frequency position of theS-SSB may be (pre-)configured. Therefore, the UE is not required toperform a hypothesis detection in order to discover the S-SSB in thecarrier.

Each SLSS may have a physical layer sidelink synchronization identity(ID), and the respective value may be equal to any one value rangingfrom 0 to 335. Depending upon any one of the above-described values thatis used, a synchronization source may also be identified. For example,values of 0, 168, 169 may indicate global navigation satellite systems(GNSS), values from 1 to 167 may indicate base stations, and values from170 to 335 may indicate that the source is outside of the coverage.Alternatively, among the physical layer sidelink synchronization IDvalues, values 0 to 167 may correspond to value being used by a network,and values from 168 to 335 may correspond to value being used outside ofthe network coverage.

FIG. 14 shows a terminal performing V2X or sidelink communication towhich an exemplary embodiment of the present invention can be applied.

Referring to FIG. 14 , in V2X/sidelink communication, the term terminalmay mainly refer to a terminal (or equipment) used by a user. However,in case a network equipment, such as a base station, transmits andreceives signals in accordance with a communication scheme between thenetwork equipment and a user equipment (UE) (or terminal), the basestation may also be viewed as a type of user equipment (or terminal).

User equipment 1 (UE1) may select a resource unit corresponding to aspecific resource within a resource pool, which refers to a set ofresources, and UE1 may then be operated so as to transmit a sidelinksignal by using the corresponding resource unit. User equipment 2 (UE2),which corresponds to a receiving UE, may be configured with a resourcepool to which UE1 can transmit signals, and may then detect signals ofUE1 from the corresponding resource pool.

Herein, in case UE1 is within a connection range of the base station,the base station may notify the resource pool. Conversely, in case UE1is outside connection range of the base station, another UE may notifythe resource pool or a pre-determined resource may be used.

Generally, a resource pool may be configured in a plurality of resourceunits, and each UE may select one resource unit or a plurality ofresource units and may use the selected resource unit(s) for itssidelink signal transmission.

FIG. 15 shows an exemplary configuration of a resource unit to which anexemplary embodiment of the present invention can be applied.

Referring to FIG. 15 , the total frequency resources of the resourcepool may be divided into NF number of resource units, the total timeresources of the resource pool may be divided into NT number of resourceunits. Therefore, a total of NF*NT number of resource units may bedefined in the resource pool. FIG. 15 shows an example of a case wherethe corresponding resource pool is repeated at a cycle of NT number ofsubframes.

As shown in FIG. 15 , one resource unit (e.g., Unit #0) may beperiodically and repeatedly indicated. Alternatively, in order toachieve a diversity effect in the time or frequency level (ordimension), an index of a physical resource unit to which a logicalresource unit is mapped may be changed to a pre-determined pattern inaccordance with time. In such resource unit structure, the resource poolmay refer to a set of resource units that can be used for a transmissionthat is performed by a user equipment (UE), which intends to transmitsidelink signals.

The resource pool may be segmented to multiple types. For example,depending upon the content of a sidelink signal being transmitted fromeach resource pool, the resource pool may be divided as described below.

(1) Scheduling Assignment (SA) may correspond to a signal includinginformation, such as a position of a resource that is used for thetransmission of a sidelink data channel, a Modulation and Coding Scheme(MCS) or MIMO transmission scheme needed for the modulation of otherdata channels, a Timing Advance (TA), and so on. The SA may also bemultiplexed with sidelink data within the same resource unit and maythen be transmitted, and, in this case, an SA resource pool may refer toa resource pool in which the SA is multiplexed with the sidelink dataand then transmitted. The SA may also be referred to as a sidelinkcontrol channel.

(2) A Physical Sidelink Shared Channel (PSSCH) may correspond to aresource pool that is used by a transmitting UE for transmitting userdata. If the SA is multiplexed with sidelink data within the sameresource unit and then transmitted, only a sidelink data channelexcluding the SA information may be transmitted from the resource poolthat is configured for the sidelink data channel. In other words, REsthat were used for transmitting SA information within a separateresource unit of the SA resource pool may still be used for transmittingsidelink data from the resource pool of a sidelink data channel.

(3) A discovery channel may correspond to a resource pool that is usedby the transmitting UE for transmitting information, such as its own ID.By doing so, the transmitting UE may allow a neighboring UE to discoverthe transmitting UE.

Even if the content of the above-described sidelink signal is the same,different resource pools may be used depending upon thetransmission/reception attribute of the sidelink signal. For example,even if the same sidelink data channel or discovery message is used, theresource pool may be identified as a different resource pool dependingupon a transmission timing decision method (e.g., whether thetransmission is performed at a reception point of the synchronizationreference signal or whether transmission is performed at the receptionpoint by applying a consistent timing advance), a resource allocationmethod (e.g., whether the base station designates a transmissionresource of a separate signal to a separate transmitting UE or whether aseparate transmitting UE selects a separate signal transmission resourceon its own from the resource pool), and a signal format (e.g., a numberof symbols occupied by each sidelink signal within a subframe or anumber of subframes being used for the transmission of one sidelinksignal) of the sidelink signal, signal intensity from the base station,a transmitting power intensity (or level) of a sidelink UE, and so on.

Hereinafter, resource allocation in a sidelink will be described indetail.

FIG. 16 shows user equipment (UE) operations according to a transmissionmode (TM) being related to sidelink/V2X communication to which anexemplary embodiment of the present invention can be applied.

(a) of FIG. 16 represents UE operations being related to transmissionmode 1 or transmission mode 3, and (b) of FIG. 16 represents UEoperations being related to transmission mode 2 or transmission mode 4.

Referring to (a) of FIG. 16 , in transmission modes 1/3, the basestation performs resource scheduling to UE1 via PDCCH (morespecifically, DCI), and UE1 performs sidelink/V2X communication with UE2according to the corresponding resource scheduling. After transmittingsidelink control information (SCI) to UE2 via physical sidelink controlchannel (PSCCH), UE1 may transmit data based on the SCI via physicalsidelink shared channel (PSSCH). In case of an LTE sidelink,transmission mode 1 may be applied to a general sidelink communication,and transmission mode 3 may be applied to a V2X sidelink communication.

Referring to (b) of FIG. 16 , in transmission modes 2/4, the UE mayschedule resources on its own. More specifically, in case of LTEsidelink, transmission mode 2 may be applied to a general sidelinkcommunication, and the UE may select a resource from a predeterminedresource pool on its own and may then perform sidelink operations.Transmission mode 4 may be applied to a V2X sidelink communication, andthe UE may carry out a sensing/SA decoding procedure, and so on, andselect a resource within a selection window on its own and may thenperform V2X sidelink operations. After transmitting the SCI to UE2 viaPSCCH, UE1 may transmit SCI-based data via PSSCH. Hereinafter, thetransmission mode may be abbreviated to mode.

In case of NR sidelink, at least two types of sidelink resourceallocation modes may be defined. In case of mode 1, the base station mayschedule sidelink resources that are to be used for sidelinktransmission. In case of mode 2, the user equipment (UE) may determine asidelink transmission resource from sidelink resources that areconfigured by the base station/network or predetermined sidelinkresources. The configured sidelink resources or the pre-determinedsidelink resources may correspond to a resource pool. For example, incase of mode 2, the UE may autonomously select a sidelink resource fortransmission. For example, in case of mode 2, the UE may assist (orhelp) sidelink resource selection of another UE. For example, in case ofmode 2, the UE may be configured with an NR configured grant forsidelink transmission. For example, in case of mode 2, the UE mayschedule sidelink transmission of another UE. And, mode 2 may at leastsupport reservation of sidelink resources for blind retransmission.

Procedures related to sensing and resource (re-)selection may besupported in resource allocation mode 2. The sensing procedure may bedefined as a process decoding the SCI from another UE and/or sidelinkmeasurement. The decoding of the SCI in the sensing procedure may atleast provide information on a sidelink resource that is being indicatedby a UE transmitting the SCI. When the corresponding SCI is decoded, thesensing procedure may use L1 SL RSRP measurement, which is based on SLDMRS. The resource (re-)selection procedure may use a result of thesensing procedure in order to determine the resource for the sidelinktransmission.

FIG. 17 shows an example where a transmission resource to which anexemplary embodiment of the present invention can be applied.

Referring to FIG. 17 , the UE may identify transmission resourcesreserved by another UE or resources being used by another UE via sensingwithin a sensing window, and, after excluding the identified resourcesfrom a selection window, the UE may randomly select a resource fromresources having low interference among the remaining resources.

For example, within the sensing window, the UE may decode the PSCCHincluding information on the cycles of the reserved resources, and,then, the UE may measure a PSSCH RSRP from resources that areperiodically determined based on the PSCCH. The UE may exclude resourceshaving the PSSCH RSRP that exceed a threshold value from the selectionwindow. Thereafter, the UE may randomly select a sidelink resource fromthe remaining resources within the selection window.

Alternatively, the UE may measure a Received signal strength indication(RSSI) of the periodic resources within the sensing window and may thendetermine the resources having low interference (e.g., the lower 20% ofthe resources). Additionally, the UE may also randomly select a sidelinkresource from the resources included in the selection window among theperiodic resources. For example, in case the UE fails to performdecoding of the PSCCH, the UE may use the above described methods.

Meanwhile, different services typically have different servicerequirements including different level of QoS as well as functionalrequirements. For this reason, when a UE wants to establish a directconnection with other UE for a certain service, it should be able todetermine whether the direct connection between this direct link canfulfil the required service requirement and thus be able to perform asort of admission control for the requested service. However, currentmechanism of device-to-device communication cannot support suchfunctionality. In this specification, the direct connection may bereferred to as a PC5 RRC connection, and the device-to-devicecommunication may be referred to as sidelink communication. In thisspecification, a remote UE may be referred to as a first UE ortransmitting UE, and a host UE may be referred to as a second UE orreceiving UE.

The procedure (messaging protocol) proposed below can be realized asdirect RRC protocol. This realization requires introduction of the belowmessage in RRC specification. If these direct RRC message are generated,the UE delivers the RRC messages to the PDCP entity applicable for ordedicated to the control plane of direct communication such that suchdirect RRC message is prioritized over other sidelink data transmission.Alternatively, the procedure (messaging protocol) proposed below can berealized as peer UE-to-peer UE PC5 signalling protocol defined at NASlayer.

FIG. 18 shows a connection establishment procedure according to anembodiment of the present invention.

Referring to FIG. 18 , in step S1810, the first UE may transmit a directconnection request message to request establish direct connection setupbetween the first UE and other UE (e.g. potential host UE or potentialsecond UE) for service(s) requested by the first UE. For instance, thefirst UE may send the direct connection request message via broadcast byincluding broadcast L2 ID in the L2 header of the direct connectionrequest message. In this specification, the direct connection may bereferred to as a direct communication, an inter-UE communication, a PC5RRC connection, a RRC connection or a connection. In this specification,the direct connection request message may be referred to as a directcommunication request message, an inter-UE communication requestmessage, a PC5 RRC connection request message, a RRC connection requestmessage or a connection request message.

If L1 destination ID may be indicated over e.g. physical sidelinkcontrol channel to inform the transmission of the direct connectionrequest message via broadcast, a broadcast L1 ID as destination ID maybe indicated. If L1 destination ID may be indicated over e.g. physicalsidelink control channel to inform resource reservation for transmissionof the direct connection request message via broadcast, a broadcast L1ID as destination ID may be indicated. L2 destination ID for broadcastmay be indicated in MAC header for the transmitted transport block.

If the first UE already identified the ID of the potential second UE,the first UE may send the direct connection request message via unicastby addressing the potential second UE within the destination field forthe transmission of this message. If L1 destination ID is indicated overe.g. physical sidelink control channel to inform the transmission of thedirect connection request message via unicast, a unicast L1 ID asdestination ID may be indicated. If L1 destination ID is indicated overe.g. physical sidelink control channel to inform resource reservationfor transmission of the direct connection request message via unicast, aunicast L1 ID as destination ID may be indicated. If L2 destination IDis indicated in MAC header of the transmitted transport block such thatreceiving MAC is able to identify that this transport block is forunicast traffic. The direct connection request message may include atleast one of the following information:

1) Service information that the first UE wants to get

The interesting/requested service may be indicated by service Identifier(SID) or service code (SCD). Multiple services may be indicated bylisting the SIDs or SCDs.

The priority of services which indicates the importance of services. Thepotential second UE may use this information when admission control ofservices are needed due to the scarce of the resources or capabilities.ProSe Per-Packet Priority (PPPP) may be used to indicate the priority.Alternatively, the new priority dedicated for service admission controlmay be introduced.

2) Requested QoS information

The requested QoS information may indicate the required/desired QoSlevel for the requested service. The requested QoS information may needto be indicated per service level, if multiple services are requested.The requested QoS information may include at least one of the followingQoS information:

2.1) Required QCI value or 5QI or new QoS indicator value representingthe (partial) set of the QoS parameters: payload (bytes), transmissionrate (message/sec or packets/sec), maximum end-to-end latency (ms),target communication range, reliability (%) or data rate (Mbps). Thedata rate may further indicate at least one of the followinginformation:

-   -   Average data rate which indicates the desired data rate when        channel is not congested.    -   Minimum data rate which indicates the minimum data rate which        the associated services require to maintain the service. If the        service requires guaranteed bit rate, this information is        necessarily included.    -   Aggregated Maximum Bit Rate (AMBR) which indicates the maximum        data rate to be supported over the requested PC5 direct        communication.

2.2) If QCI or 5QI or the new QoS indicator cannot represent all theparameters presented above, the parameters not covered by the QoSindicator may be indicated together with the QoS indicator.

2.3) Sidelink traffic flow type (bearer type) which indicates whetherthe requested services requires guaranteed bit rate (GBR) or non-GBR.

2.4) Priority of each service: PPPP may be used to indicate thepriority.

2.5) Minimum required communication range (meters)

2.6) Need for QoS prediction

-   -   The need for QoS prediction may indicate whether the requested        service requires QoS prediction functionality, where QoS        prediction functionality allows the served UE to be aware of the        change of the expected QoS in advance (e.g. a certain QoS level        is expected to degrade in 10 seconds).    -   The need for QoS prediction may further indicate the minimum        timing advance by which the QoS change notification based on QoS        prediction is notified to the first UE prior to the moment of        actual QoS change.    -   The need for QoS prediction may further indicate the need for        periodic update of QoS prediction notification to the first UE.        The need for QoS prediction may further indicate the periodicity        of the requested QoS prediction notification.

2.7) Need for supporting guaranteed QoS

-   -   This IE may indicate whether the requested service requires        guaranteed QoS. The required QoS may be defined for a certain        period of time. The period of time may indicate the minimum time        period for which the promised QoS can be ensured. In this usage        of the IE, the IE may further indicate the time period for which        the requested QoS needs to be maintained    -   This IE may be indicated with a minimum probability that the        requested QoS needs to be satisfied.

3) Connection information

Type of direct connection: this IE may be either of “unicast” or“multicast” or “broadcast”. In case this IE is not present, it indicates“unicast” by default.

Direction of direct connection: this IE may be either of “unidirectionalwith receiving only” or “unidirectional transmitting only” or“bidirectional”.

Each service information being requested should be associated with onetype of direct connection request. For this purpose, the connectioninformation IE may need to be indicated per each service ID beingrequested.

4) Max waiting time for direct connection setup

This information may indicate the maximum waiting time for which thefirst UE can wait until establishment of requested direct communicationsince the connection is initially requested. To make sure that thepotential second UE know when the connection was initially requested,the time information indicating the moment of initially constructing thedirect connection request at the first UE may need to be included in thedirect connection request message.

5) Sidelink capability information

The sidelink capability information may indicate the capabilities of thefirst UEs available for transmission and or reception over the requesteddirect communication. Transmission capabilities and receptioncapabilities may need to be indicated separately.

The sidelink capability information may further indicate the securitycapability of the first UE. This may include the supported cipheringalgorithms and possibly related parameters. This may include thesupported integrity check algorithms and possibly related parameters.

The sidelink capability information may further indicate the supportedsecurity capability. This may include supported ciphering algorithms.This may include supported integrity protection algorithms. This mayinclude supported length of security key.

The sidelink capability information may indicate at least one of thefollowing capability information for direction communication:

5.1) Information on the supported modulation order

5.2) Information on the supported channel coding scheme

5.3) Information on the supported RAT

5.4) Maximum transmit power for each supported RAT

5.5) Supported frequency bands for each supported RAT

5.6) Supported bandwidth for each supported band for directcommunication

5.7) Supported band combination for direct communication: supported bandcombination for simultaneous reception for direct communication, and/orsupported band combination for simultaneous transmission for directcommunication

5.8) Supported band combination for concurrent Uu and directcommunication: supported band combination for concurrent reception,supported band combination for concurrent transmission, supported bandcombination for concurrent reception of Uu and transmission of directcommunication, and/or supported band combination for concurrenttransmission of Uu and reception of direct communication

5.9) Duplex per RAT or per band per RAT: Half duplex or Full duplex

5.10) HARQ capabilities: this information may indicate the HARQcapabilities. This information may further indicate maximum number ofHARQ processes. This information may further indicate at least one ofthe following information:

-   -   Support of HARQ feedback    -   Support of HARQ combining    -   Supported HARQ feedback signalling methods: HARQ feedback over        sidelink control channel, HARQ feedback over sidelink data        channel (i.e. HARQ feedback is piggy-bagged over data        transmission), and/or HARQ feedback over MAC Control Element

5.11) Maximum number of layers (spatial multiplexing) per frequency orper RAT

5.12) Supported synchronization sources: support of GNSS as syncreference source, support of UE-transmitted synchronization (e.g. SLSS)as sync reference source, and/or support of network synchronization(downlink synchronization) as sync reference source

6) Initial ID of the first UE;

This ID may be layer-2 ID of the first UE. If this L2 ID is indicated,the potential second UE needs to use this L2 ID to address the first UEby including the L2 ID in the L2 header of the message destined to thefirst UE. If this L2 ID is not indicated, the potential second UE needsto use the L2 ID included in the L2 header of this direct connectionrequest message.

Alternatively, this ID may be upper layer ID of the first UE. This IDmay be used by upper layer of the receiving second UE to address thefirst UE

7) UE status information

7.1) UE location: this information may indicate the location of thefirst UE. This information may be used by the receiving UE (i.e. secondUE) to determine whether the direct connection to be established canprovide the requested QoS for the requested services. This informationmay be used for initial power control by calculating the distancebetween the first UE and the second UE. This information may be used forinitial beamforming.

7.2) Channel Status information: this information may indicate thechannel statistics perceived by the first UE. This information mayindicate the statistics of channel utilization used by directcommunications as well as potential/unidentified interferers.

Channel quality: this information may indicate the channel quality ofthe direct link between the first UE and the second UE. The first UE maymeasure the link quality by measuring the strength/quality of the signaltransmitted by the second UE.

Channel utilization statistics: the statistics may be measured energylevel. More compactly, the statistics may be channel busy ratio (CBR)measurements where the channel is detected as busy if the measuredenergy level on the concerned resource is higher than a threshold. Thethreshold used to measure the CBR may needs to be indicated. Thisinformation may indicate how much each resource group is being occupiedin unit of percent (%). For instance, the resource group can be achannel define over a specific frequency range. For instance, theresource group can be a group of resource blocks. This information mayneed to be collected and signalled per each resource group. If the firstUE supports direct communication over multiple RATs, this IE needs to besignalled per RAT of those RATs. This information may need to becollected and signalled per each carrier frequency if more than onefrequency can be used for direct communication. This information mayneed to be collected and signalled per each resource pool per each RATthat can be possibly used for the direct communication being requested.

7.3) On-going sidelink service information

The on-going sidelink service information may indicate the on-goingsidelink service(s) and/or the attributes of the services for which thefirst UE has been transmitting or willing to transmit packets oversidelink. The second UE may use this information to better estimate thereception opportunities of the first UE by taking half-duplexconstraints into account and thus to better select the transmissionresources.

The on-going sidelink service information may indicate the on-goingsidelink service(s) and/or the attributes of the services for which thefirst UE has been receiving or is willing to receive packets oversidelink. The second UE may use this information to better select thetransmission resources by taking e.g. the priority of the on-goingservice of the first UEs and new services to be offered to the first UEinto account. This information may be useful to alleviate the potentialcollision of reception resource at the first UE when the transmissionfrom the second UE to the first UE may collide with transmission fromother UE to the first UE.

The on-going sidelink service information may be delivered as a part ofthe channel status information. The on-going sidelink serviceinformation may further indicate the required priority of each on-goingservice, e.g. ProSe Per Packet Priority (PPPP). The on-going sidelinkservice information may further indicate the required reliability ofeach on-going service, e.g. ProSe Per Packet Reliability (PPPR).

The on-going sidelink service information may further indicate therequired QoS information of the service. For instance, this may indicateaverage payload size, data rate, and/or maximum delay that are requiredby the on-going service. For instance, this may indicate required QCIvalue required by the on-going service. For instance, this may indicaterequired 5QI value required by the on-going service.

The on-going sidelink service information may further indicate at leastone of the following information on each on-going service:

-   -   Average payload (bytes) of the message transmitted/received for        the concerned service    -   Average transmission rate (message/sec or transport blocks/sec)        in case of on-going service that transmits message    -   Average message arrival rate, which indicates the arrival rate        of the message from upper layer for transmission in case of        on-going service that transmits message    -   Average message arrival rate, which indicates the arrival rate        of the message from lower layer after reception in case of        on-going service that receives message    -   Average transmission delay (ms) (measured as the time duration        between when the message is arrived at radio protocol stack and        when the message is actually transmitted over the air)    -   Estimated transmission reliability (%)

This estimate related to transmission reliability can be made byconsidering the statistics of the received HARQ ACK and/or HARQ NACK.The average reliability can be averaged over a moving fixed size timewindow. For instance, the average reliability may be obtained based onthe equation 1.

$\begin{matrix}{{{average}\mspace{14mu}{reliability}} = \frac{{the}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{total}\mspace{14mu}{received}\mspace{14mu}{HARQ}\mspace{14mu}{ACKs}}{{the}\mspace{14mu}{total}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{total}\mspace{14mu}{transmitted}\mspace{14mu}{TBs}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Alternatively, the average reliability can be average by applyingexponentially weighted moving average (EWMA) over time. For instance,the average reliability may be obtained based on the equation 2.average reliability(n)=(1−k)*average reliability(n−1)+k*instantaneousreliability(n)  [Equation 2]

where k is small value close to zero (e.g. 0.1) and the instantaneousreliability is measured as averaging the ratio defined above.

This estimate related to transmission reliability can be made bycollecting the statistics of PDCP transmit buffer used by the concernedservice. The average reliability can be measured by averaging the ratioof the number of transmitted packets to the number of the packetsarrived from upper layers.

-   -   Estimated reception reliability (%)

This estimate related to reception reliability can be made byconsidering the transmitted HARQ ACK and/or HARQ NACK. The same averagemethod defined above for calculating transmission reliability can beused;

-   -   To inform the second UE of the overall traffic statistics for        the concerned service, it is sufficient to collect the        statistics over entire frequencies over which the packets of the        concerned service have been transmitted, and it is also        sufficient to collect the statics over entire frequencies over        which the packets of all the concerned services have been        transmitted. To assist the second UE to choose better resource        configuration for the first UE, the above statistics may need to        be collected and indicated per frequency/channel.

The on-going sidelink service information may further indicate at leastone of the following information to help the second UE avoid using theresources that are/can be used by the first UEs:

-   -   Information on the transmission resources (time/frequency        information). The information on the transmission resources may        indicate the resources reserved for pending or future        transmissions of the concerned on-going service. For instance,        the information on the transmission resources may indicate the        pattern of the resources to be used for the concerned        transmissions. For instance, the information on the transmission        resources may indicate a) time offset that can be used to        identify the starting point of the reservation interval, and b)        retransmission interval (e.g. gap between initial and        retransmission), c) the reservation interval (e.g. data        transmission periodicity), and/or d) reservation termination        time (e.g. reservation is valid until the reservation        termination time). The information on the transmission resources        may indicate the resource set that is dedicatedly allocated for        the concerned on-going service. The information on the        transmission resources may be constructed by collectively        merging the transmission resources related to multiple on-going        services to reduce signalling overhead, rather than signalling        the transmission resources per service. The information on the        transmission resources may be interpreted as prohibitive        transmission resources by the second UEs if the first UE is        subject to half-duplex constraint.    -   Information on the reception resources (time/frequency        information). The information on the reception resources may        indicate the resources (or resource pool) that can be used for        reception of the concerned on-going service. For instance, the        information on the reception resources may indicate the pattern        of the resources to be used for the concerned reception. The        information on the reception resources may indicate the resource        set that is dedicatedly allocated for the concerned on-going        service. The information on the reception resources may be        constructed by collectively merging the reception resources        related to multiple on-going services to reduce signalling        overhead, rather than signalling the reception resources per        service. The information on the reception resources may be        interpreted as prohibitive transmission resources by the second        UEs in case the first UE is subject to hidden node problem.

7.4) In-coverage/out-of-coverage information

The in-coverage/out-of-coverage information may indicate whether thefirst UE is currently inside network or out of network coverage. If thefirst UE supports multiple RATs, it may need to signal the informationper each RAT. If the first UE is configured with dual connectivity, itmay indicate the connectivity status with respect to the primary cell.The in-coverage/out-of-coverage information may be useful when theprimary cell can control the connection for the concerned directcommunication being requested.

7.5) Current sync source information: this information may indicatewhether the first UE can receive GNSS signal.

7.6) Transmit power used to transmit the direct connection requestmessage: this information can be used by the second UE to estimate thepathloss between the first UE and the second UE and to determine andcontrol the transmission power of the first UE as well as thetransmission power of the second UE.

8) UE subscription information or subscribed PLMN information

The subscribed PLMN information may indicate the home PLMN of the UE forcellular services including PC5. The subscribed PLMN information mayindicate the PLMN(s) for which PC5 operations are granted for the UE.The subscribed PLMN information may indicate the PLMN(s) for which PC5operations for the requested services are granted for the UE. Thesubscribed PLMN information may need to signalled per service. Thesubscribed PLMN information may further indicate at least one of thefollowing information:

-   -   Home PLMN per RAT: this is the case when UE supports multiple        RATs and each RAT is associated with same or different home        PLMNs (e.g. Dual SIM Dual Active, DSDA)    -   Supported RATs per allowed PLMN;    -   Allowed operation: this indicates which of the following        operations are allowed for the PLMNs (e.g. transmission only,        reception only, or both transmission and reception)

9) Preferred configuration (preferred scheduling mode for transmissionof the first UE)

The preferred configuration may indicate the preferred way of schedulingfor transmission of the first UE. The preferred configuration mayinclude ‘both the second UE-scheduling and the first UE autonomousscheduling (=don't care)’ or ‘only the first UE autonomous scheduling’.For instance, the first UE may set this IE to “only the first UEautonomous scheduling” if it does not lose the freedom of transmissionresource selection.

For failure handing, upon sending the direct connection request message,the first UE starts a timer T_CONN. If T_CONN expires, the first UEconsiders that the connection request fails. The first UE starts a timerT_INT.

While the T_INT is running, the first UE is not allowed to requestdirect connection setup for the same service with the same QoSrequirements. The T_INT is managed per a set of services requested inthe same message. Therefore, multiple T_INT may be running at the sametime. The value of T_CONN and T_INT can be configured to the first UE bynetwork or those values can be preset.

While T_INT is running, the first UE is allowed to initiate directconnection setup, if it want to request a new service. While T_INT isrunning, the first UE is allowed to initiate direct connection setupwhile T_INT is running if it want to request a new service. While T_INTis running, the first UE is allowed to initiate direct connection setupwhile T_INT is running if it wants to request a service that resulted inthe running T_INT with different QoS requirements.

In step S1820, the second UE may estimate supportable QoS and evaluateadmissible services. Upon receiving the direct connection requestmessage from other UE (i.e. first UE), a potential second UE performsthe following to determine if it accepts the direct connection requestreceived from the first UE:

-   -   if the potential second UE can offer at least one of the        requested services by considering its capabilities with respect        to service information included in the direct connection request        message, and/or    -   if the potential second UE can support the requested type of        direct connection, and/or    -   if the potential second UE can support the requested QoS for the        services supported by the potential second UE by considering its        capabilities, first UE capabilities, link status/utilization        based on the monitoring results from the second UE perspective        as well as first UE's UE status information included in the        direct connection request message, and/or    -   if the potential second UE ensures that the first UE has a valid        subscription on the requested services, e.g. in terms of PLMN,        and/or    -   if the potential second UE ensures that the first UE is not        forbidden for the requested service and for the requested type        of direct connection.

If all these conditions are satisfied, the potential second UE maydecide to accept the direct connection request. If at least one of theseconditions is satisfied, the potential second UE may decide to acceptthe direct connection request. Depending on considered embodiments, asubset of the above conditions can be checked.

In step S1830, if the potential second UE accepts the direct connectionrequest, the second UE may send the direct connection accept message.Otherwise, the potential second UE may send direct connection rejectmessage. In FIG. 18 , it is assumed that the second UE accepts thedirect connection request. In this specification, the direct connectionaccept message may be referred to as a direct communication acceptmessage, an inter-UE communication accept message, a PC5 RRC connectionaccept message, a RRC connection accept message or a connection acceptmessage. The direct connection accept message may include at least oneof the following information:

1) Accepted service ID/code

If the first UE has requested a single service ID/code, then thisID/code needs not be included.

2) Reason for service denials

For the service that is not accepted, the reason of the service denialmay be indicated. The reason may be at least one of ‘request fromunauthorized UE’, ‘request from forbidden UE’, or ‘lack of capability inoffering requested QoS’. The cause ‘lack of capability in offeringrequested QoS’ may further indicate ‘lack of transmission resources’,‘lack of reception resources’, or ‘lack of both transmission resourcesand reception resources’.

3) Traffic flow information

For the accepted service(s), the associated traffic flow ID may beindicated. This traffic flow ID may be used when host addresses oridentifies a particular traffic flow of the connection for sidelinkcommunication. This flow ID may be used for radio resource configurationas given below.

Traffic flow ID construction rule:

Alt.1) Traffic flow ID is uniquely assigned across all traffic flowsincluding “unidirectional” service for both directions and“bidirectional” services.

Alt.2) Traffic flow ID is uniquely assigned across traffic flows havingthe same direction. Therefore, the traffic flow ID needs informationindicating the direction of communication (e.g. “forward (second tofirst)” or “reverse (first to second)”) to be uniquely distinguishableacross all traffic flows including “unidirectional” service for bothdirections and “bidirectional” services.

The traffic flow ID may be different per direction of directcommunication of “bidirectional” services

4) Offered QoS information

4.1) Expected QoS

The expected QoS information may indicate the expected QoS level to beexperienced for the accepted service. The format of IEs that can beincluded in the requested QoS information in the direct connectionrequest message can be reused here. The expected QoS information mayneed to be indicated per accepted service (ID). The expected QoSinformation may be indicated per QoS parameters requested by the firstUE for the requested service being accepted.

4.2) Support of guaranteed QoS

This may indicate whether the offered QoS can be guaranteed. Therequired QoS may be defined for a certain period of time. The period oftime may indicate the minimum time period for which the promised QoS canbe ensured. In this usage of the IE, the IE may further indicate thetime period for which the offered QoS can be maintained. This IE may beindicated together with a minimum probability of satisfying the offeredQoS. The first UE will utilize this probability to determine whether itproceeds/accepts the unicast link establishment with the QoS leveloffered by the second UE.

5) Sidelink capability information

The sidelink capability information may indicate the capabilities of thesecond UEs about transmission and/or reception over direct communicationinterface. Transmission capabilities and reception capabilities may needto be indicated separately. This second UE includes receptioncapabilities if the direction of direct communication requested by thefirst UE is “unidirectional with transmit only” or “bidirectional”.

6) Radio resource configuration for sidelink

The radio resource configuration for sidelink may indicate the radioresource parameters to be used for the direct communication link beingestablished. This IE may include at least one of the following:

6.1) Initial ID of the second UE

This ID can be upper layer ID of the second UE. This ID can be used byupper layer of the first UE to address the second UE. This ID can belayer-2 ID of the second UE. If this L2 ID is indicated, the first UEneeds to use this L2 ID to address the second UE by including the L2 IDin the L2 header of the message destined to the second UE. If this L2 IDis not indicated, the first UE needs to use the L2 ID included in the L2header of this direct connection accept message.

6.2) Sidelink resource pool structure which indicates the followinginformation:

-   -   Control channel structure: time-frequency resources comprising        physical sidelink control channel    -   Data channel structure: time-frequency resources comprising        physical sidelink data channel

Multiple resource pools may be indicated. For each resource pool,associated services/traffic flow ID(s) may be indicated. Alternatively,for each service/traffic flow ID, the associated resource pool(s) may beindicated. Note that this mapping of resource pool to service/trafficflow ID implies the mapping of frequency (channel) to service.

6.3) Scheduling mode

This indicates the transmission resource selection scheme that the firstUE shall use.

-   -   Network-scheduled resource selection; this can be set only if        the first UE has indicated that it is in network coverage.    -   Second UE-scheduled resource selection;    -   First UE autonomous resource selection;

This configuration can be per UE. Alternatively, this configuration isprovided per service/traffic flow such that a service/traffic flow withmore stringent QoS requirements are differently treated possibly with atighter control.

6.4) Synchronization configuration

This indicates the synchronization reference source to be used fordirect communication being established. For instance, information mayindicate that GNSS is a prioritized synchronization reference. Forinstance, information may indicate that UE-transmitted synchronization(e.g. SLSS) is a prioritized synchronization reference. For instance,information may indicate that downlink synchronization signal is aprioritized synchronization reference. For instance, information mayindicate the priority of synchronization reference among downlinksynchronization signal, GNSS and UE-transmitted synchronization signal.For instance, information may indicate that the second UE is asynchronization reference. In this case, the information may besynchronization signal identification information, e.g. SLSS ID to beused by the second UE for SLSS transmission. For instance, informationmay indicate that the first UE is a synchronization reference. In thiscase, the information may be synchronization signal identificationinformation, e.g. SLSS ID to be used by the first UE for SLSStransmission. For instance, information may indicate that distributedsynchronization reference is used. If no information is provided onsynchronization configuration, the first UE keeps using the presentsynchronization method.

6.5) HARQ configuration

-   -   This configuration can be per UE. Alternatively, this        configuration is provided per service/traffic flow such that a        service/traffic flow with more stringent QoS requirements are        differently treated possibly with a tighter control.    -   HARQ retransmission configuration: This configuration may        indicate whether HARQ retransmission is based on HARQ feedback        or whether HARQ retransmission is performed without HARQ        feedback.    -   Feedback configuration: HARQ feedback signalling method to be        used for the direct communication. This configuration may        indicate whether HARQ feedback is required or not. This        information may need to be indicated per each communication        direction (from/to first UE) depending on the capabilities of        HARQ of the first UE and the second UE as well as direction of        direct communication being established. This information may        needs to be indicated per communication direction per accepted        service/traffic flow;    -   Number of HARQ processes, e.g., number of HARQ processes to be        used by the first UE or number of HARQ processes to be used by        the second UE    -   Number of retransmissions: The number of HARQ retransmission may        be indicated. The number of HARQ retransmission may be        configured for the case when HARQ retransmission is configured        to be performed without HARQ feedback (i.e. blind HARQ        retransmission). In this case the number of blind        retransmissions may be further defined or indicated by the        configuration. In this case, HARQ combining is applied to the        received transport blocks including a new transmission and up to        the number of retransmissions. The number of HARQ retransmission        may be configured for the case when HARQ retransmission is        configured to be performed with HARQ feedback (i.e. HARQ        feedback based HARQ retransmission). In this case the number of        retransmissions may indicate the outcome of the (re)transmission        for which HARQ feedback is generated. For example, 1        retransmission number is configured for HARQ with HARQ feedback,        the second UE needs to send HARQ NACK if the collective outcome        of receiving two transmissions (one new transmission+one        retransmission) indicates an unsuccessful transmissions.

6.6) Transmit power control configuration

-   -   This configuration can be per UE. Alternatively, this        configuration is provided per service/traffic flow such that a        service/traffic flow with more stringent QoS requirements are        differently treated possibly with a tighter control.    -   Power control method, e.g., open loop power control or closed        loop power control    -   Power control parameter including base transmit power (Po)        and/or step power adjustment level (Pi). For instance, the first        UE needs to transmit with transmit power Po when ignoring Pi.        For instance, signalled Pi can be a single integer value with        either plus or minus value. For instance, signalled Pi can be a        value within a range. The first UE needs to transmit with        transmit power Po+accumulated value of received Pi's.

7) Transaction ID

This transaction ID uniquely identifies the message contents. If themessage is retransmitted to achieve diversity gain due to less-robustnature of D2D networks, the transaction ID is the same. For the samedirect connection setup procedure, the transaction ID is the same.

The direct connection accept message is desirably addressed only to thefirst UE by setting the destination field of this message to first UE IDsuch that other UE receiving this message can ignore the message. Thedestination field for the transmission of the message may exist inlayer1 where control channel indicates the field and layer 2 where MACheader indicates the field.

In case that the second UE transmits a direct connection reject message,the direct connection reject message may include the reason for denialIE to inform the first UE of the reason of the reject of directconnection establishment.

For failure handling, upon sending the direct connection accept message,the potential second UE starts a timer T_CONN2. If T_CONN2 expires, thepotential second UE considers that the connection establishment fordirect communication fails.

In step S1840, upon receiving the direct connection accept message, thefirst UE may perform the following to determine if the first UE acceptsthe direct connection accept:

-   -   if the accepted services are sufficient/acceptable for the first        UE to establish the direct connection with the second UE, and/or    -   if the expected QoS for the accepted services are        sufficient/acceptable for the first UE to establish the direct        connection with the second UE, and/or    -   if the first UE ensures that the second UE has a valid        subscription to provide the accepted services, e.g. in terms of        PLMN, and/or    -   if the first UE ensures that the second UE is not forbidden for        providing the requested service.

In step S1850, if all or at least one of these conditions are satisfied,the first UE may decide to establish the direct connection with thesecond UE and send direct connection confirm message carrying thefollowing information:

-   -   Confirmed service information including a list of services that        the first UE wants over the direct connection being established    -   ID of the second UE to which the direct connection confirm        message is destined.    -   Transaction ID which uniquely identifies the message contents.        If the message is retransmitted to achieve diversity gain due to        less-robust nature of D2D networks, the transaction ID is the        same. For the same direct connection setup procedure, the        transaction ID is the same.

In step S1860, the first UE may receive data for confirmed services fromthe second UE. For instance, the data for confirmed services may bereceived via established connection (e.g. PC5 RRC connection) betweenthe first UE and the second UE.

FIG. 19 shows a connection establishment procedure according to anembodiment of the present invention.

Referring to FIG. 19 , in step S1910, the first UE may transmit a directconnection request message to request establish direct connection setupbetween the first UE and other UE (e.g. potential second UE A andpotential second UE B) for service(s) requested by the first UE. Thedirect connection request message has already been described in detailin step S1810 of FIG. 18 , and therefore, detailed description of stepS1910 will be omitted.

In step S1920, the potential second UE A and the potential second UE Bmay estimate supportable QoS and evaluate admissible services. Uponreceiving the direct connection request message from other UE (i.e.first UE), the potential second UE A and the potential second UE Bperforms the following to determine if it accepts the direct connectionrequest received from the first UE:

-   -   if the potential second UE can offer at least one of the        requested services by considering its capabilities with respect        to service information included in the direct connection request        message, and/or    -   if the potential second UE can support the requested type of        direct connection, and/or    -   if the potential second UE can support the requested QoS for the        services supported by the potential second UE by considering its        capabilities, first UE capabilities, link status/utilization        based on the monitoring results from the second UE perspective        as well as first UE's UE status information included in the        direct connection request message, and/or    -   if the potential second UE ensures that the first UE has a valid        subscription on the requested services, e.g. in terms of PLMN,        and/or    -   if the potential second UE ensures that the first UE is not        forbidden for the requested service and for the requested type        of direct connection.

If all these conditions are satisfied, the potential second UE maydecide to accept the direct connection request. If at least one of theseconditions is satisfied, the potential second UE may decide to acceptthe direct connection request. Depending on considered embodiments, asubset of the above conditions can be checked.

In step S1930, if the potential second UE A and the potential second UEB accepts the direct connection request, the potential second UE A andthe potential second UE B may send the direct connection accept message.Otherwise, the potential second UE A and the potential second UE B maysend direct connection reject message. In FIG. 19 , it is assumed thatthe potential second UE A and the potential second UE B accepts thedirect connection request. The direct connection accept message hasalready been described in detail in step S1830 of FIG. 18 , andtherefore, detailed description of step S1930 will be omitted.

In step S1940, upon receiving the direct connection accept message, thefirst UE may perform the following to determine if the first UE acceptsthe direct connection accept:

-   -   if the accepted services are sufficient/acceptable for the first        UE to establish the direct connection with the potential second        UE A or the potential second UE B, and/or    -   if the expected QoS for the accepted services are        sufficient/acceptable for the first UE to establish the direct        connection with the potential second UE A or the potential        second UE B, and/or    -   if the first UE ensures that the potential second UE A or the        potential second UE B has a valid subscription to provide the        accepted services, e.g. in terms of PLMN, and/or    -   if the first UE ensures that the potential second UE A or the        potential second UE B is not forbidden for providing the        requested service.

In step S1950, if all or at least one of these conditions are satisfied,the first UE may decide to establish the direct connection with thepotential second UE A or the potential second UE B, and send a directconnection confirm message or a direct connection denial message. InFIG. 19 , it is assumed that the first UE decides to establish thedirect connection with the potential second UE A, not the potentialsecond UE B. Then, the first UE may send the direct connection confirmmessage to the potential second UE A, and send the direct connectiondenial message to the potential second UE B. The direct connectionconfirm message has already been described in detail in step S1850 ofFIG. 18 , and therefore, detailed description of step S1950 related tothe direct connection confirm message will be omitted.

Specifically, since there may exist multiple potential second UEs thateach provide direct connection accept with different offeredservices/different level of QoS, the first UE may wait some time tocollect possibly multiple direct connection accept messages since itsends the direct connection request message. After collecting the directconnection accept messages(s), the first UE chooses the best second UEbased on the offered services and supported QoS and responds to thechosen second UE by sending the direct connection confirm messageaddressed to the selected second UE (i.e. potential second UE A of FIG.19 ). When choosing the best second UE, the UE may prioritize the secondUE that provides the best QoS for the service of higher priority.

If the first UE decides to reject the direct connection with thepotential second UE B, the first UE may send a direct connection denialmessage to the potential second UE B. In specification, the directconnection denial message may be referred to as a direct communicationdenial message, a direct connection reject message, a directcommunication reject message, denial message or reject message. Thedirect connection denial message may include ID of the second UE towhich the direct communication reject message is destined.

Alternatively, if the first UE decides to reject the direct connectionwith the potential second UE B, the first UE does not send any message.In this embodiment, the potential second UE B will eventually identifythe failure of the connection of direct communication based on expiry ofa timer that started upon transmission of the direct communicationaccept message.

Note that the direct connection confirm message is necessary to resolvethe case where more than two host UEs replies with direct communicationaccept message. This works as follows. If the potential second UE Breceives, from the first UE to which the potential second UE B sends thedirect connection accept message, the direct connection confirm messagethat includes a ID of the first and a ID of the potential second UE Athat is different from a ID of the potential second UE B included in thedirect connection accept message, the potential second UE B may considerthat the connection establishment procedure fails. And, the potentialsecond UE B may stop any further processing related to the directconnection request message received from the first UE and release anyresources prepared for the first UE.

Upon sending the direct connection confirm message, the first UE mayconsider that the requested direct connection is established for theconfirmed services. Alternatively it is possible that the first UEconsiders that the requested direct connection is established for theconfirmed services after a fixed time (T_gap) has passed upon sendingthe direct connection confirm message. The T_gap may be signalled in thedirect connection accept message. Upon receiving the direct connectionconfirm message, the potential second UE A may consider that therequested direct connection is established for the confirmed services.

In step S1960, the first UE may receive data for confirmed services fromthe potential second UE A. For instance, the data for confirmed servicesmay be received via established connection (e.g. PC5 RRC connection)between the first UE and the potential second UE A.

FIG. 20 shows a connection establishment procedure according to anembodiment of the present invention.

Referring to FIG. 20 , in step S2010, the first UE may transmit a directconnection request message to request establish direct connection setupbetween the first UE and other UE (e.g. potential second UE A andpotential second UE B) for service(s) requested by the first UE. Thedirect connection request message has already been described in detailin step S1810 of FIG. 18 , and therefore, detailed description of stepS2010 will be omitted.

In step S2020, the potential second UE A and the potential second UE Bmay estimate supportable QoS and evaluate admissible services. Uponreceiving the direct connection request message from other UE (i.e.first UE), the potential second UE A and the potential second UE Bperforms the following to determine if it accepts the direct connectionrequest received from the first UE:

-   -   if the potential second UE can offer at least one of the        requested services by considering its capabilities with respect        to service information included in the direct connection request        message, and/or    -   if the potential second UE can support the requested type of        direct connection, and/or    -   if the potential second UE can support the requested QoS for the        services supported by the potential second UE by considering its        capabilities, first UE capabilities, link status/utilization        based on the monitoring results from the second UE perspective        as well as first UE's UE status information included in the        direct connection request message, and/or    -   if the potential second UE ensures that the first UE has a valid        subscription on the requested services, e.g. in terms of PLMN,        and/or    -   if the potential second UE ensures that the first UE is not        forbidden for the requested service and for the requested type        of direct connection.

If all these conditions are satisfied, the potential second UE maydecide to accept the direct connection request. If at least one of theseconditions is satisfied, the potential second UE may decide to acceptthe direct connection request. Depending on considered embodiments, asubset of the above conditions can be checked. In FIG. 20 , it isassumed that the potential second UE B accepts the direct connectionrequest while the potential second UE A rejects the direct connectionrequest.

In step S2030, if the potential second UE A rejects the directconnection request, the potential second UE A may send a directconnection reject message to the first UE. The direct connection rejectmessage may include the reason for denial IE to inform the first UE ofthe reason of the reject of direct connection establishment.

In step S2040, if the potential second UE B accepts the directconnection request, the potential second UE B may send the directconnection accept message. The direct connection accept message hasalready been described in detail in step S1830 of FIG. 18 , andtherefore, detailed description of step S2040 will be omitted.

In step S2050, upon receiving the direct connection accept message, thefirst UE may perform the following to determine if the first UE acceptsthe direct connection accept:

-   -   if the accepted services are sufficient/acceptable for the first        UE to establish the direct connection with the potential second        UE B, and/or    -   if the expected QoS for the accepted services are        sufficient/acceptable for the first UE to establish the direct        connection with the potential second UE B, and/or    -   if the first UE ensures that the potential second UE B has a        valid subscription to provide the accepted services, e.g. in        terms of PLMN, and/or    -   if the first UE ensures that the potential second UE B is not        forbidden for providing the requested service.

If all or at least one of these conditions are satisfied, the first UEmay decide to establish the direct connection with the potential secondUE B, and send a direct connection confirm message. The directconnection confirm message has already been described in detail in stepS1850 of FIG. 18 , and therefore, detailed description of step S2050related to the direct connection confirm message will be omitted.

In step S2060, the first UE may receive data for confirmed services fromthe potential second UE B. For instance, the data for confirmed servicesmay be received via established connection (e.g. PC5 RRC connection)between the first UE and the potential second UE B.

FIG. 21 shows a connection establishment procedure according to anembodiment of the present invention.

Referring to FIG. 21 , in step S2110, the first UE may transmit a directconnection request message to request establish direct connection setupbetween the first UE and other UE (e.g. potential second UE A andpotential second UE B) for service(s) requested by the first UE. Thedirect connection request message has already been described in detailin step S1810 of FIG. 18 , and therefore, detailed description of stepS2110 will be omitted.

In step S2120, the potential second UE A and the potential second UE Bmay estimate supportable QoS and evaluate admissible services. Uponreceiving the direct connection request message from other UE (i.e.first UE), the potential second UE A and the potential second UE Bperforms the following to determine if it accepts the direct connectionrequest received from the first UE:

-   -   if the potential second UE can offer at least one of the        requested services by considering its capabilities with respect        to service information included in the direct connection request        message, and/or    -   if the potential second UE can support the requested type of        direct connection, and/or    -   if the potential second UE can support the requested QoS for the        services supported by the potential second UE by considering its        capabilities, first UE capabilities, link status/utilization        based on the monitoring results from the second UE perspective        as well as first UE's UE status information included in the        direct connection request message, and/or    -   if the potential second UE ensures that the first UE has a valid        subscription on the requested services, e.g. in terms of PLMN,        and/or    -   if the potential second UE ensures that the first UE is not        forbidden for the requested service and for the requested type        of direct connection.

If all these conditions are satisfied, the potential second UE maydecide to accept the direct connection request. If at least one of theseconditions is satisfied, the potential second UE may decide to acceptthe direct connection request. Depending on considered embodiments, asubset of the above conditions can be checked. In FIG. 21 , it isassumed that the potential second UE A accepts the direct connectionrequest for service A and the potential second UE B accepts the directconnection request for service B.

In step S2130, if the potential second UE A accepts the directconnection request for the service A, the potential second UE A may sendthe direct connection accept message including accepted service ID/codeto the first UE. If the potential second UE B accepts the directconnection request for the service B, the potential second UE B may sendthe direct connection accept message including accepted service ID/codeto the first UE. The direct connection accept message has already beendescribed in detail in step S1830 of FIG. 18 , and therefore, detaileddescription of step S2130 will be omitted.

In step S2140, upon receiving the direct connection accept message, thefirst UE may perform the following to determine if the first UE acceptsthe direct connection accept:

-   -   if the accepted services are sufficient/acceptable for the first        UE to establish the direct connection with the potential second        UE A or the potential second UE B, and/or    -   if the expected QoS for the accepted services are        sufficient/acceptable for the first UE to establish the direct        connection with the potential second UE A or the potential        second UE B, and/or    -   if the first UE ensures that the potential second UE A or the        potential second UE B has a valid subscription to provide the        accepted services, e.g. in terms of PLMN, and/or    -   if the first UE ensures that the potential second UE A or the        potential second UE B is not forbidden for providing the        requested service.

In step S2150, if all or at least one of these conditions are satisfied,the first UE may decide to establish the direct connection with thepotential second UE A and the potential second UE B, and send a directconnection confirm message for the service A and the service B to thepotential second UE A and the potential second UE B, respectively. Thatis, the first UE may send the direct connection confirm message for theservice A to the potential second UE A, and send the direct connectionconfirm message for the service B to the potential second UE B.According to an embodiment of the present invention, it is possible thatthe first UE chooses different second UE for different services. In thiscase, the first UE may send multiple direct connection confirm messagesto each potential second UE selected for each service. The directconnection confirm message has already been described in detail in stepS1850 of FIG. 18 , and therefore, detailed description of step S2150related to the direct connection confirm message will be omitted.

In step S2160, the first UE may receive data for confirmed service Afrom the potential second UE A. For instance, the data for confirmedservice A may be received via established connection (e.g. PC5 RRCconnection) between the first UE and the potential second UE A. Also,the first UE may receive data for confirmed service B from the potentialsecond UE B. For instance, the data for confirmed service B may bereceived via established connection (e.g. PC5 RRC connection) betweenthe first UE and the potential second UE B.

FIG. 22 shows a connection establishment procedure according to anembodiment of the present invention.

Referring to FIG. 22 , in step S2210, the potential second UE may send adirect connection request message to the first UE. The direct connectionrequest message may include at least one of the following information:

1) Available service information

The available service information may indicate services which the hostUE is able to offer. The available service information may furtherindicate the type of supported direct connection. For instance, the typeof supported direct connection may be at least one of unicast,multicast, receive only, transmit only or both receive and transmit.

2) Supported QoS level for the available services, which indicates theQoS level for the service potentially offered by the host UE

3) Supported sidelink capability information

4) Flag that this is a service announcement

The Flag helps other second UE to distinguish the direct connectionrequest sent by the first UE from the direct connection request sent bythe potential second UE. Note that this direct connection requestmessage may be essentially for broadcasting the available services thatcan be offered.

In step S2220, the first UE may send a direct connection accept messageto the potential second UE. The direct connection accept message mayinclude at least one of the following information:

1) The information included in the direct connection request message ofthe step S1810 may be included in the direct connection accept messageof the step S2220.

2) ID of the potential second UE may be included in the directconnection accept message to resolve the potential ID confusion issue.

The direct connection accept message can be addressed by unicast ID overlayer 1 and layer 2. The first UE starts T_CONN3 upon sending the directconnection accept message. Upon expiry of T_CONN3, the first UEconsiders that the connection establishment fails.

In step S2230, the potential second UE may send a direct connectionconfirm message to the first UE. The direct connection confirm messagemay include the information included in the direct connection acceptmessage of the step S1830.

The potential second UE starts T_CONN4 upon sending the directconnection confirm message. Upon receiving the direct connection confirmmessage, the first UE stops T_CONN3. If the potential second UEidentifies that the requested service is actually on-going (e.g. bymonitoring the packet transmission over the establishment link over bothcommunication direction), it resets T_CONN4. Upon expiry of T_CONN4, thepotential second UE considers that the connection establishment failsand releases the connection and therefore release resources prepared forthe first UE.

FIG. 23 shows a connection establishment procedure according to anembodiment of the present invention.

Referring to FIG. 23 , in step S2310, the potential second UE may send adirect communication service announcement message to the first UE. Thedirect communication service announcement message may include availableservice information which indicates services which the host UE is ableto offer.

In step S2320, the first UE may send a direct communication requestmessage to the potential second UE. The direct communication requestmessage may include at least one of the following information:

1) The information included in the direct connection request message ofthe step S1810 may be included in the direct communication requestmessage of the step S2320.

2) ID of the potential second UE may be included in the directcommunication request message to resolve the potential ID confusionissue.

The direct communication request message can be addressed by unicast IDover layer 1 and layer 2. The first UE starts T_CONN3 upon sending thedirect communication request message. Upon expiry of T_CONN3, the firstUE considers that the connection establishment fails.

In step S2330, the potential second UE may send a direct communicationconfirm message to the first UE. The direct communication confirmmessage may include the information included in the direct connectionaccept message of the step S1830.

The potential second UE starts T_CONN4 upon sending the directcommunication confirm message. Upon receiving the direct communicationconfirm message, the first UE stops T_CONN3. If the potential second UEidentifies that the requested service is actually on-going (e.g. bymonitoring the packet transmission over the establishment link over bothcommunication direction), it resets T_CONN4. Upon expiry of T_CONN4, thepotential second UE considers that the connection establishment failsand releases the connection and therefore release resources prepared forthe first UE.

FIG. 24 shows a connection establishment procedure according to anembodiment of the present invention.

Referring to FIG. 24 , in step S2410, the first UE may transmit a directconnection request message to request establish direct connection setupbetween the first UE and other UE (e.g. potential second UE or secondUE) for service(s) requested by the first UE. For instance, the first UEmay send the direct connection request message via broadcast byincluding broadcast L2 ID in the L2 header of the direct connectionrequest message.

If L1 destination ID may be indicated over e.g. physical sidelinkcontrol channel to inform the transmission of the direct connectionrequest message via broadcast, a broadcast L1 ID as destination ID maybe indicated. If L1 destination ID may be indicated over e.g. physicalsidelink control channel to inform resource reservation for transmissionof the direct connection request message via broadcast, a broadcast L1ID as destination ID may be indicated. L2 destination ID for broadcastmay be indicated in MAC header for the transmitted transport block.

If the first UE already identified the ID of the potential second UE,the first UE may send the direct connection request message via unicastby addressing the potential second UE within the destination field forthe transmission of this message. If L1 destination ID is indicated overe.g. physical sidelink control channel to inform the transmission of thedirect connection request message via unicast, a unicast L1 ID asdestination ID may be indicated. If L1 destination ID is indicated overe.g. physical sidelink control channel to inform resource reservationfor transmission of the direct connection request message via unicast, aunicast L1 ID as destination ID may be indicated. If L2 destination IDis indicated in MAC header of the transmitted transport block such thatreceiving MAC is able to identify that this transport block is forunicast traffic. The direct connection request message may include atleast one of the following information:

1) Service information that the first UE wants to get

The interesting/requested service may be indicated by service Identifier(SID) or service code (SCD). Multiple services may be indicated bylisting the SIDs or SCDs.

2) Requested QoS information

The requested QoS information may indicate the required/desired QoSlevel for the requested service. The requested QoS information may needto be indicated per service level, if multiple services are requested.The requested QoS information may include at least one of the followingQoS information:

2.1) Required QCI value or 5QI or new QoS indicator value representingthe (partial) set of the QoS parameters: payload (bytes), transmissionrate (message/sec or packets/sec), maximum end-to-end latency (ms),target communication range, reliability (%) or data rate (Mbps). Thedata rate may further indicate at least one of the followinginformation:

-   -   Average data rate which indicates the desired data rate when        channel is not congested.    -   Minimum data rate which indicates the minimum data rate which        the associated services require to maintain the service. If the        service requires guaranteed bit rate, this information is        necessarily included.    -   Aggregated Maximum Bit Rate (AMBR) which indicates the maximum        data rate to be supported over the requested PC5 direct        communication.

2.2) If QCI or 5QI or the new QoS indicator cannot represent all theparameters presented above, the parameters not covered by the QoSindicator may be indicated together with the QoS indicator.

2.3) Minimum required communication range (meters)

2.4) Need for QoS prediction

-   -   The need for QoS prediction may indicate whether the requested        service requires QoS prediction functionality, where QoS        prediction functionality allows the served UE to be aware of the        change of the expected QoS in advance (e.g. a certain QoS level        is expected to degrade in 10 seconds).    -   The need for QoS prediction may further indicate the minimum        timing advance by which the QoS change notification based on QoS        prediction is notified to the first UE prior to the moment of        actual QoS change.    -   The need for QoS prediction may further indicate the need for        periodic update of QoS prediction notification to the first UE.        The need for QoS prediction may further indicate the periodicity        of the requested QoS prediction notification.

2.5) Need for supporting guaranteed QoS

-   -   This IE may indicate whether the requested service requires        guaranteed QoS. The required QoS may be defined for a certain        period of time. The period of time may indicate the minimum time        period for which the promised QoS can be ensured. In this usage        of the IE, the IE may further indicate the time period for which        the requested QoS needs to be maintained    -   This IE may be indicated with a minimum probability that the        requested QoS needs to be satisfied.

3) Connection information

Type of direct connection: this IE may be either of “unicast” or“multicast” or “broadcast”. In case this IE is not present, it indicates“unicast” by default.

Direction of direct connection: this IE may be either of “unidirectionalwith receiving only” or “unidirectional transmitting only” or“bidirectional”.

Each service information being requested should be associated with onetype of direct connection request. For this purpose, the connectioninformation IE may need to be indicated per each service ID beingrequested.

4) Max waiting time for direct connection setup

This information may indicate the maximum waiting time for which thefirst UE can wait until establishment of requested direct communicationsince the connection is initially requested. To make sure that thepotential second UE know when the connection was initially requested,the time information indicating the moment of initially constructing thedirect connection request at the first UE may need to be included in thedirect connection request message.

5) Initial ID of the first UE;

This ID may be layer-2 ID of the first UE. If this L2 ID is indicated,the potential second UE needs to use this L2 ID to address the first UEby including the L2 ID in the L2 header of the message destined to thefirst UE. If this L2 ID is not indicated, the potential second UE needsto use the L2 ID included in the L2 header of this direct connectionrequest message.

Alternatively, this ID may be upper layer ID of the first UE. This IDmay be used by upper layer of the receiving second UE to address thefirst UE

6) UE subscription information or subscribed PLMN information

The subscribed PLMN information may indicate the home PLMN of the UE forcellular services including PC5. The subscribed PLMN information mayindicate the PLMN(s) for which PC5 operations are granted for the UE.The subscribed PLMN information may indicate the PLMN(s) for which PC5operations for the requested services are granted for the UE. Thesubscribed PLMN information may need to signalled per service. Thesubscribed PLMN information may further indicate at least one of thefollowing information:

-   -   Home PLMN per RAT: this is the case when UE supports multiple        RATs and each RAT is associated with same or different home        PLMNs (e.g. Dual SIM Dual Active, DSDA)    -   Supported RATs per allowed PLMN;    -   Allowed operation: this indicates which of the following        operations are allowed for the PLMNs (e.g. transmission only,        reception only, or both transmission and reception)

For failure handing, upon sending the direct connection request message,the first UE starts a timer T_CONN. If T_CONN expires, the first UEconsiders that the connection request fails. The first UE starts a timerT_INT.

While the T_INT is running, the first UE is not allowed to requestdirect connection setup for the same service with the same QoSrequirements. The T_INT is managed per a set of services requested inthe same message. Therefore, multiple T_INT may be running at the sametime. The value of T_CONN and T_INT can be configured to the first UE bynetwork or those values can be preset.

While T_INT is running, the first UE is allowed to initiate directconnection setup, if it want to request a new service. While T_INT isrunning, the first UE is allowed to initiate direct connection setupwhile T_INT is running if it want to request a new service. While T_INTis running, the first UE is allowed to initiate direct connection setupwhile T_INT is running if it wants to request a service that resulted inthe running T_INT with different QoS requirements.

In step S2420, the second UE may estimate supportable QoS and evaluateadmissible services. Upon receiving the direct connection requestmessage from other UE (i.e. first UE), a potential second UE performsthe following to determine if it accepts the direct connection requestreceived from the first UE:

-   -   if the potential second UE can offer at least one of the        requested services, and/or    -   if the potential second UE can support the requested type of        direct connection, and/or    -   if the potential second UE ensures that the first UE has a valid        subscription on the requested services, e.g. in terms of PLMN,        and/or    -   if the potential second UE ensures that the first UE is not        forbidden for the requested service and for the requested type        of direct connection.

If all these conditions are satisfied, the potential second UE maydecide to accept the direct connection request. If at least one of theseconditions is satisfied, the potential second UE may decide to acceptthe direct connection request. Depending on considered embodiments, asubset of the above conditions can be checked.

In step S2430, if the potential second UE accepts the direct connectionrequest, the second UE may send the direct connection setup message. InFIG. 24 , it is assumed that the second UE accepts the direct connectionrequest. The direct connection setup message may include at least one ofthe following information:

1) Accepted service ID/code

If the first UE has requested a single service ID/code, then thisID/code needs not be included.

2) Traffic flow information

For the accepted service(s), the associated traffic flow ID may beindicated. This traffic flow ID may be used when host addresses oridentifies a particular traffic flow of the connection for sidelinkcommunication. This flow ID may be used for radio resource configurationas given below.

3) Sidelink capability information

The sidelink capability information may indicate the capabilities of thesecond UEs about transmission and/or reception over direct communicationinterface. Transmission capabilities and reception capabilities may needto be indicated separately. This second UE includes receptioncapabilities if the direction of direct communication requested by thefirst UE is “unidirectional with transmit only” or “bidirectional”.

4) Radio resource configuration for sidelink

The radio resource configuration for sidelink may indicate the radioresource parameters to be used for the direct communication link beingestablished. This IE may include at least one of the following:

4.1) Initial ID of the second UE

This ID can be upper layer ID of the second UE. This ID can be used byupper layer of the first UE to address the second UE. This ID can belayer-2 ID of the second UE. If this L2 ID is indicated, the first UEneeds to use this L2 ID to address the second UE by including the L2 IDin the L2 header of the message destined to the second UE. If this L2 IDis not indicated, the first UE needs to use the L2 ID included in the L2header of this direct connection setup message.

4.2) Sidelink resource pool structure which indicates the followinginformation:

-   -   Control channel structure: time-frequency resources comprising        physical sidelink control channel    -   Data channel structure: time-frequency resources comprising        physical sidelink data channel

Multiple resource pools may be indicated. For each resource pool,associated services/traffic flow ID(s) may be indicated. Alternatively,for each service/traffic flow ID, the associated resource pool(s) may beindicated. Note that this mapping of resource pool to service/trafficflow ID implies the mapping of frequency (channel) to service.

4.3) Scheduling mode

This indicates the transmission resource selection scheme that the firstUE shall use.

-   -   Network-scheduled resource selection; this can be set only if        the first UE has indicated that it is in network coverage.    -   Second UE-scheduled resource selection;    -   First UE autonomous resource selection; First UE autonomous        resource selection can be a default mode.

This configuration can be per UE. Alternatively, this configuration isprovided per service/traffic flow such that a service/traffic flow withmore stringent QoS requirements are differently treated possibly with atighter control.

4.4) Synchronization configuration

This indicates the synchronization reference source to be used fordirect communication being established. For instance, information mayindicate that GNSS is a prioritized synchronization reference. Forinstance, information may indicate that UE-transmitted synchronization(e.g. SLSS) is a prioritized synchronization reference. For instance,information may indicate that downlink synchronization signal is aprioritized synchronization reference. For instance, information mayindicate the priority of synchronization reference among downlinksynchronization signal, GNSS and UE-transmitted synchronization signal.For instance, information may indicate that the second UE is asynchronization reference. In this case, the information may besynchronization signal identification information, e.g. SLSS ID to beused by the second UE for SLSS transmission. For instance, informationmay indicate that the first UE is a synchronization reference. In thiscase, the information may be synchronization signal identificationinformation, e.g. SLSS ID to be used by the first UE for SLSStransmission. For instance, information may indicate that distributedsynchronization reference is used. If no information is provided onsynchronization configuration, the first UE keeps using the presentsynchronization method.

4.5) HARQ configuration;

-   -   This configuration can be per UE. Alternatively, this        configuration is provided per service/traffic flow such that a        service/traffic flow with more stringent QoS requirements are        differently treated possibly with a tighter control.    -   HARQ retransmission configuration: This configuration may        indicate whether HARQ retransmission is based on HARQ feedback        or whether HARQ retransmission is performed without HARQ        feedback.    -   Feedback configuration: HARQ feedback signalling method to be        used for the direct communication. This configuration may        indicate whether HARQ feedback is required or not. This        information may need to be indicated per each communication        direction (from/to first UE) depending on the capabilities of        HARQ of the first UE and the second UE as well as direction of        direct communication being established. This information may        needs to be indicated per communication direction per accepted        service/traffic flow;    -   Number of HARQ processes, e.g., number of HARQ processes to be        used by the first UE or number of HARQ processes to be used by        the second UE    -   Number of retransmissions: The number of HARQ retransmission may        be indicated. The number of HARQ retransmission may be        configured for the case when HARQ retransmission is configured        to be performed without HARQ feedback (i.e. blind HARQ        retransmission). In this case the number of blind        retransmissions may be further defined or indicated by the        configuration. In this case, HARQ combining is applied to the        received transport blocks including a new transmission and up to        the number of retransmissions. The number of HARQ retransmission        may be configured for the case when HARQ retransmission is        configured to be performed with HARQ feedback (i.e. HARQ        feedback basedHARQ retransmission). In this case the number of        blind retransmissions may indicate the outcome of the        transmissions for which HARQ feedback is generated. For example,        1 retransmission number is configured for HARQ with HARQ        feedback, the second UE needs to send HARQ NACK if the        collective outcome of receiving two transmissions (one new        transmission+one retransmission) indicates an unsuccessful        transmissions.

4.6) Transmit power control configuration

-   -   This configuration can be per UE. Alternatively, this        configuration is provided per service/traffic flow such that a        service/traffic flow with more stringent QoS requirements are        differently treated possibly with a tighter control.    -   Power control method, e.g., open loop power control or closed        loop power control    -   Power control parameter including base transmit power (Po)        and/or step power adjustment level (Pi). For instance, the first        UE needs to transmit with transmit power Po when ignoring Pi.        For instance, signalled Pi can be a single integer value with        either plus or minus value. For instance, signalled Pi can be a        value within a range. The first UE needs to transmit with        transmit power Po+accumulated value of received Pi's.

5) Transaction ID

This transaction ID uniquely identifies the message contents. If themessage is retransmitted to achieve diversity gain due to less-robustnature of D2D networks, the transaction ID is the same. For the samedirect connection setup procedure, the transaction ID is the same.

The direct connection setup message is desirably addressed only to thefirst UE by setting the destination field of this message to first UE IDsuch that other UE receiving this message can ignore the message. Thedestination field for the transmission of the message may exist in layer1 where control channel indicates the field and layer 2 where MAC headerindicates the field.

For failure handling, upon sending the direct connection setup message,the potential second UE starts a timer T_CONN2. If T_CONN2 expires, thepotential second UE considers that the connection establishment fordirect communication fails.

In step S2440, upon receiving the direct connection setup message, thefirst UE may perform the following to determine if the first UE acceptsthe direct connection setup:

-   -   if the accepted services are sufficient/acceptable for the first        UE to establish the direct connection with the second UE, and/or    -   if the first UE ensures that the second UE has a valid        subscription to provide the accepted services, e.g. in terms of        PLMN, and/or    -   if the first UE ensures that the second UE is not forbidden for        providing the requested service.

In step S2450, if all or at least one of these conditions are satisfied,the first UE may decide to establish the direct connection with thesecond UE and send direct connection complete message carrying thefollowing information:

-   -   Confirmed service information including a list of services that        the first UE wants over the direct connection being established    -   ID of the second UE to which the direct connection complete        message is destined.

Further, the direct connection complete message may also include thefollowing information:

-   -   Sidelink capability information, and/or    -   UE status information, and/or    -   Requested QoS information, and/or    -   Connection information

The above four information may increase the size of the directconnection complete message. If the size of the direct connectioncomplete message is larger than a threshold, the first UE may defersending the information in the information transfer message.

If the first UE intends to send the information transfer messageimmediately after the direct connection complete message, the first UEmay include a kind of information indicating that in the directconnection complete message that the information transfer messagetransmission follows. Upon receiving this information or indication, thesecond UE defers sending the direct connection control message untilreceiving the information transfer message. If this information orindication is not included in the direct connection complete message,the second UE immediately sends the direct connection control messageupon receiving the direct connection complete message.

If the first UE decides to reject the direct connection with the secondUE, it sends the direct connection reject message including ID of thesecond UE to which the direct connection reject message is destined.

Alternatively, if the first UE decides to reject the direct connectionwith the second UE, it does not send any message. In this embodiment,the potential second UE will eventually identify the failure of theconnection of direct communication based on expiry of a timer thatstarted upon transmission of the direct connection setup message.

Note that the direct connection complete message is necessary to resolvethe case where more than two host UEs replies with direct communicationsetup message. This works as follows. If the potential second UE Breceives, from the first UE to which the potential second UE B sends thedirect connection setup message, the direct connection complete messagethat includes a ID of the first and a ID of the potential second UE Athat is different from a ID of the potential second UE B included in thedirect connection setup message, the potential second UE B may considerthat the connection establishment procedure fails. And, the potentialsecond UE B may stop any further processing related to the directconnection request message received from the first UE and release anyresources prepared for the first UE.

For the direct connection request message to the direct connectioncomplete message for the same transaction of direct connection setup,the same transaction ID is included in the direct connection requestmessage to the direct connection complete message.

In step S2460, after sending the direct connection complete message, thefirst UE may send the information transfer message to the second UE. Theinformation transfer message may include at least one of the followinginformation:

-   -   Sidelink capability information, and/or    -   UE status information, and/or    -   Requested QoS information, and/or    -   Connection information

Any of the information already included in the direct connectioncomplete message is not included again in the information transfermessage as long as the contents are the same.

In step S2470, upon receiving the direct connection complete messagethat is not followed by the information transfer message or receivingthe information transfer message, the second UE may send the directconnection control message. The direct connection control message mayinclude at least one of the following information:

-   -   Offered QoS information, and/or    -   Radio resource configuration for sidelink, and/or    -   Transaction ID, and/or    -   Activation time of the radio resource configuration included in        the information transfer message. Upon receiving this        information, the first UE keeps applying the previously used        configuration until the time indicated by the activation time        and applies the radio resource configuration in the information        transfer message since the time indicated by the activation        time. The value of activation time can be preset. If this        information is not included, the first UE applies the        configuration in the direct connection control message upon        receiving the direct connection control message.

Upon sending the direct connection control message, the second UE startsa timer T_5.

Alternatively, upon receiving the direct connection complete messagethat is not followed by the information transfer message or receivingthe information transfer message which includes the informationindicating the required quality of service and/or required sidelinkcapabilities that cannot be supported by the second UE, the second UEsends the direct connection release message to the first UE, includingin the direct connection release message the cause of the connectionrelease.

In step S2480, upon receiving the direct connection control message, thefirst UE sends the direct connection control complete message to thesecond UE. The direct connection control complete message may includethe transaction ID of the direct connection control message thattriggered sending the direct connection control complete message. Uponreceiving the direct connection control complete message, the second UEstops T_5 and considers that the first UE is ready to apply the newconfiguration provided in the direct connection complete message and maysend control message to the first UE to activate the configurationincluded in the direct connection control message. If T_5 expires, thesecond UE considers that transmission of the direct connection controlmessage fails.

Hereinafter, according to an embodiment of the present invention,provisioning of connection setup by a network will be described.

A network (e.g. base station) may configure the unicast setup policy tothe UE. For instance, the unicast setup policy may be ‘via directcommunication procedure only’ or ‘via network authorization wheneverpossible, and via direct communication procedure otherwise’.

The first UE may check the unicast setup policy before the unicastsetup. The second UE may check if the first UE that has sent the directconnection request is authorized UE for the direct connection. For this,the second UE query this UE by providing some information. For instance,the network check if allowance, then sends to the second UE allowance,then direct setup is allowed.

This invention may propose procedures of direct connection management(e.g. connection setup) that allows admission control as well asprediction of supportable QoS based on assistance information exchangefor direct communication, where the assistance information istransmitted/received during a direct connection setup procedure orduring normal direct communication that may have been initiatedwith/without an explicit direct connection setup procedure.Specifically, this invention may allow UEs (e.g. the first UE and thesecond UE) to negotiate QoS by exchanging properly designed assistanceinformation, and the negotiation may be performed during/after thedirect connection setup procedure. This invention may allow the secondUE to make the best estimate of the supported QoS over the potentialdirect connection link for the requested services with requested QoS.Further, this invention may enable the second UE to choose theadmissible services for the first UE. In addition, this invention mayallow the first UE to choose the best second UE when multiple second UEcandidates are available.

FIG. 25 shows a method for performing sidelink communication by a firstapparatus (9010) according to an embodiment of the present invention.

Referring to FIG. 25 , in step S2510, the first apparatus (9010) mayreceive, from a second apparatus (9020), restriction information relatedto the sidelink communication between the first apparatus (9010) and thesecond apparatus (9020).

In step S2520, the first apparatus (9010) may perform the sidelinkcommunication with the second apparatus (9020) based on the restrictioninformation.

For instance, performing the sidelink communication with the secondapparatus (9020) may comprise: determining whether or not to establish aconnection with the second apparatus (9020) based on the restrictioninformation.

For instance, performing the sidelink communication with the secondapparatus (9020) may comprise: determining transmission parameters forthe sidelink communication based on the restriction information.

According to an embodiment of the present invention, the restrictioninformation may include information on transmission resources orreception resources of the second apparatus (9020). In this case,performing the sidelink communication with the second apparatus (9020)may comprise: selecting transmission resources for the sidelinkcommunication based on the information on transmission resources orreception resources included in the restriction information. In thiscase, further, performing the sidelink communication with the secondapparatus (9020) may comprise: performing sidelink transmission with theselected transmission resources. For instance, the transmissionresources selected by the first apparatus (9010) may be different fromthe transmission resources or the reception resources of the secondapparatus (9020). Further, the second apparatus (9020) may selecttransmission resources for the sidelink communication based on theinformation on transmission resources or reception resources of thesecond apparatus (9020).

According to an embodiment of the present invention, the restrictioninformation may include HARQ capability of the second apparatus (9020).The HARQ capability of the second apparatus (9020) may include at leastone of whether the second apparatus (9020) supports sidelink HARQfeedback, whether the second apparatus supports HARQ combining, ormaximum number of the sidelink HARQ processes supported by the secondapparatus (9020). In this case, performing the sidelink communicationwith the second apparatus (9020) may comprise: determining whetherretransmissions need to be performed based HARQ feedback ontransmissions or whether retransmissions need to be performed withoutHARQ feedback (i.e. blind retransmission needs to be used in case thesecond apparatus does not support HARQ feedback but supports HARQcombining) determining transmission resources and/or retransmissionresources for the sidelink communication based on the HARQ capabilityincluded in the restriction information. In this case, further,performing the sidelink communication with the second apparatus (9020)may comprise: performing sidelink transmission and/or sidelinkretransmission with the determined transmission resources and/orretransmission resources.

According to an embodiment of the present invention, the restrictioninformation may include at least one of required quality of service(QoS) level for a service requested by the second apparatus (9020),sidelink capability information of the second apparatus (9020), initialID of the second apparatus (9020), UE status information of the secondapparatus (9020), UE subscription information of the second apparatus(9020), or scheduling mode preferred by the second apparatus (9020). Theabove-described various information included in the restrictioninformation has already been described in detail in FIG. 18 , andtherefore, detailed description of various information included in therestriction information will be omitted.

For instance, the first apparatus (9010) or the second apparatus (9020)may include at least one of a terminal, a user equipment (UE), awireless device, a wireless communication device, a vehicle, a vehicleequipped with an autonomous driving function, a connected car, aunmanned aerial vehicle (UAV), an artificial intelligence (AI) module, arobot, an augmented reality (AR) device, a virtual reality (VR) device,a mixed reality (MR) device, a hologram device, a public safety device,a machine type communication (MTC) device, an internet of things (IoT)device, a medical device, a pin-tech device (or financial device), asecurity device, or a climate/environmental device.

Hereinafter, apparatus to which the present invention is applicable willbe described.

FIG. 26 shows a wireless communication apparatus according to anembodiment of the present invention.

Referring to FIG. 26 , a wireless communication system may include afirst apparatus (9010) and a second apparatus (9020).

The first apparatus (9010) may be a base station, a network node, atransmitting terminal, a receiving terminal, a wireless device, awireless communication device, a vehicle, a vehicle equipped with anautonomous driving function, a connected car, a unmanned aerial vehicle(UAV), an artificial intelligence (AI) module, a robot, an augmentedreality (AR) device, a virtual reality (VR) device, a mixed reality (MR)device, a hologram device, a public safety device, a machine typecommunication (MTC) device, an internet of things (IoT) device, amedical device, a pin-tech device (or financial device), a securitydevice, a climate/environmental device, devices related to 5G services,or other devices related to fourth industrial revolution fields.

The second apparatus (9020) may be a base station, a network node, atransmitting terminal, a receiving terminal, a wireless device, awireless communication device, a vehicle, a vehicle equipped with anautonomous driving function, a connected car, a unmanned aerial vehicle(UAV), an artificial intelligence (AI) module, a robot, an augmentedreality (AR) device, a virtual reality (VR) device, a mixed reality (MR)device, a hologram device, a public safety device, a machine typecommunication (MTC) device, an internet of things (IoT) device, amedical device, a pin-tech device (or financial device), a securitydevice, a climate/environmental device, devices related to 5G services,or other devices related to fourth industrial revolution fields.

For example, the terminal may include a cellular phone, a smart phone, alaptop computer, a digital broadcasting terminal, a personal digitalassistants (PDA), a portable multimedia player (PMP), a navigation, aslate PC, a tablet PC, an ultrabook, a wearable device such as asmartwatch, a smart glass, or a head mounted display (HMD)), etc. Forexample, the HMD may be a display device worn on a head. For example, anHMD may be used to implement the VR, AR, or MR.

For example, the UAV may be a flying object that is not ridden by peoplebut that flies by radio control signals. For example, the VR device mayinclude a device that implements an object or background in a virtualworld. For example, the AR device may include a device that connects andimplements the object or background in the real world to the object orbackground in a real world. For example, the MR device may include adevice that fuses and implements the object or background in the virtualworld with the object or background in the real world. For example, thehologram device may include a device for implementing a 360-degreestereoscopic image by recording and reproducing stereoscopic informationby utilizing a phenomenon of interference of light generated by the twolaser lights meeting with each other, called holography. For example,the public safety device may include a video relay device or a videodevice that may be worn by a body of a user. For example, the MTC deviceand the IoT device may be a device which does not require direct humanintervention or manipulation. For example, the MTC device and the IoTdevice may include a smart meter, a vending machine, a thermometer, asmart bulb, a door lock, or various sensors. For example, the medicaldevice may be a device used for diagnosing, treating, alleviating,treating, or preventing a disease. For example, the medical device maybe a device used for diagnosing, treating, alleviating, or correcting aninjury or disability. For example, the medical device may be a deviceused for inspecting, replacing, or modifying a structure or function.For example, the medical device may be a device used for controllingpregnancy. For example, the medical device may include a medicaltreatment device, a surgical device, an (in vitro) diagnostic device, ahearing aid or a (medical) procedure device, and the like. For example,the security device may be a device installed to prevent a risk that mayoccur and to maintain safety. For example, the security device may be acamera, a CCTV, a recorder, or a black box. For example, the pin-techdevice may be a device capable of providing financial services such asmobile payment. For example, the pin-tech device may include a paymentdevice or a point of sales (POS). For example, the climate/environmentaldevice may include a device for monitoring or predicting aclimate/environment.

The first apparatus (9010) may include at least one processor, such as aprocessor (9011), at least one memory, such as a memory (9012), and atleast one transceiver, such as a transceiver (9013). The processor(9011) may perform the functions, procedures, and/or methods describedabove. The processor (9011) may perform one or more protocols. Theprocessor (9011) may perform one or more layers of a radio interfaceprotocol. The memory (9012) may be connected to the processor (9011) andstore various types of information and/or commands. The transceiver(9013) may be connected to the processor (9011) and controlled totransmit/receive a radio signal. The transceiver (9013) may be connectedto one or more of the antennas (9014-1 to 9014-n). In the presentspecification, the n antennas may be the number of physical antennas orthe number of logical antenna ports.

The second apparatus (9020) may include at least one processor, such asa processor (9021), at least one memory, such as a memory (9022), and atleast one transceiver, such as a transceiver (9023). The processor(9021) may perform the functions, procedures, and/or methods describedabove. The processor (9021) may implement one or more protocols. Forexample, the processor (9021) may implement one or more layers of theradio interface protocol. The memory (9022) may be connected to theprocessor (9021) and store various types of information and/or commands.The transceiver (9023) may be connected to the processor (9021) andcontrolled to transmit/receive a radio signal. The transceiver (9023)may be connected to one or more of the antennas (9024-1 to 9024-n).

The memory (9012) and/or the memory (9022) may be each connected insideor outside the processor (9011) and/or the processor (9021) andconnected to other processors through various techniques such as wiredor wireless connection.

According to an embodiment of the present invention, the processor(9011) may control the transceiver (9013) to receive, from a secondapparatus (9020), restriction information related to the sidelinkcommunication between the first apparatus (9010) and the secondapparatus (9020). Then, the processor (9011) may perform the sidelinkcommunication with the second apparatus (9020) based on the restrictioninformation. The procedures and/or schemes suggested in the presentspecification may be applied to the first apparatus (9010) and thesecond apparatus (9020).

FIG. 27 shows a wireless communication device according to an exemplaryembodiment of the present invention.

FIG. 27 may correspond to a more detailed diagram of a first device orsecond device (9010, 9020) shown in FIG. 26 . However, the wirelesscommunication device of FIG. 27 is not limited to the user equipment(UE). The wireless communication device may correspond to a randomappropriate mobile computer device being configured to perform one ormore embodiments of the present invention, such as a vehiclecommunication system or device, a wearable device, a portable computer,a smartphone, and so on.

Referring to FIG. 27 , the user equipment (UE) may include at least oneor more processors (e.g., DSP or microprocessor), such as a processor(9110), a transceiver (9135), a power management module (9105), anantenna (9140), a battery (9155), a display (9115), a keypad (9120), aGlobal Positioning System (GPS) chip (9160), a sensor (9165), a memory(9130), (optionally) a subscriber identification module (SIM) card(9125), a speaker (9145), a microphone (9150), and so on. The userequipment may include one or more antennas.

The processor (9110) may be configured to perform the above-describedfunctions, procedures and/or methods of the present invention. Accordingto an exemplary embodiment of the present invention, the processor(9110) may perform one or more protocols, such as layers of a radiointerface protocol.

The memory (9130) is connected to the processor (9110) and may storeinformation related to the operation of the processor (9110). The memory(9130) may be located inside or outside of the processor (9110), and thememory (9130) may also be connected to another processor via diversetechnologies, such as wired or wireless connection.

A user may input diverse types of information (e.g., commandinformation, such as phone numbers) by using diverse techniques, such aspushing a button of the keypad (9120) or voice activation using themicrophone (9150). The processor (9110) may receive and process userinformation and may execute proper functions, such as making a phonecall by dialing a phone number. For example, data (e.g., operation data)may be searched from the SIM card (9125) or the memory (9130) in orderto execute the respective functions. As another example, the processor(9110) may receive and process GPS information from the GPS chip (9160)in order to execute functions related to the position of the UE, such asvehicle navigation, map service, and so on. As yet another example, theprocessor (9110) may indicate diverse types of information and data tothe display (9115) for referential usage or convenience of the user.

The transceiver (9135) may be connected to the processor (9110) maytransceive (transmit and receive) radio signals, such as RF signals. Theprocessor (9110) may control the transceiver (9135) so that thetransceiver (9135) can initiate communication and transmit radio signalsincluding diverse types of information or data, such as voicecommunication data. The transceiver (9135) may include a receiver and atransmitter in order to transmit or receive radio signals. The antenna(9140) may easily perform transmission and reception of radio signals.According to the exemplary embodiment, when receiving radio signals, thetransceiver (9135) may forward and convert the signals to a basebandfrequency in order to process the signals by using the processor (9110).The processed signals may be processed in accordance with diversetechnologies, such as converting the processed signals to informationthat can be heard by being outputted through the speaker (9145) orinformation that can be read.

According to the exemplary embodiment of the present invention, thesensor (9165) may be connected to the processor (9110). The sensor(9165) may include at least one detection device being configured todiscover diverse forms of information including speed, acceleration,light, oscillation, proximity, position, image, and so on, but not beinglimited only to the information types listed above. The processor (9110)may receive and process sensor information acquired from the sensor(9165) and may execute diverse types of functions, such as collisionprevention, automatic driving, and so on.

In the example of FIG. 27 , diverse components (e.g., camera, USB port,and so on) may be further included in the UE. For example, a camera maybe connected to the processor (9110) and may be used for diverseservices, such as automatic driving, vehicle safety service, and so on.

As described above, FIG. 27 is merely an example of the user equipment,and, therefore, the embodiment of the same will not be limited only tothis. For example, some of the components (e.g., keypad (9120), GPS chip(9160), sensor (9165), speaker (9145), and/or microphone (9150)) may notbe implemented in some scenarios.

The processor (9011, 9021 or 9110) may include an application-specificintegrated circuit (ASIC), a separate chipset, a logic circuit, and/or adata processing unit. The memory (9012, 9022 or 9130) may include aread-only memory (ROM), a random access memory (RAM), a flash memory, amemory card, a storage medium, and/or other equivalent storage devices.The transceiver (9013, 9023 or 9135) may include a base-band circuit forprocessing a wireless signal. When the embodiment is implemented insoftware, the aforementioned methods can be implemented with a module(i.e., process, function, etc.) for performing the aforementionedfunctions. The module may be stored in the memory and may be performedby the processor (9011, 9021 or 9110). The memory (9012, 9022 or 9130)may be located inside or outside the processor (9011, 9021 or 9110), andmay be coupled to the processor (9011, 9021 or 9110) by using variouswell-known means.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

What is claimed is:
 1. A method for performing sidelink communication bya first apparatus, the method comprising: transmitting, to a secondapparatus, a direct communication request message to establish unicastlink, which includes an identifier of the first apparatus andinformation regarding at least one service type, wherein the directcommunication request message further includes information regarding asecurity capability of the first apparatus, and wherein based on that anidentifier of the second apparatus is provided, the direct communicationrequest message further includes information regarding the identifier ofthe second apparatus; transmitting, to the second apparatus, quality ofservice (QoS) information related to the at least one service type;receiving, from the second apparatus, a direct communication acceptmessage including an identifier of the second apparatus and the QoSinformation related to the at least one service type; and performing thesidelink communication based on the unicast link between the firstapparatus and the second apparatus.
 2. The method of claim 1, whereinthe unicast link between the first apparatus and the second apparatus isestablished for the at least one service type based on the directcommunication request message and the direct communication acceptmessage.
 3. The method of claim 1, wherein the identifier of the firstapparatus is an upper layer identifier of the first apparatus, and theidentifier of the second apparatus is an upper layer identifier of thesecond apparatus.
 4. The method of claim 1, wherein the directcommunication request message includes security information for anestablishment of security between the first apparatus and the secondapparatus.
 5. The method of claim 1, wherein the QoS informationincludes at least one QoS indicator value representing guaranteed bitrate (GBR) or non-GBR.
 6. The method of claim 1, wherein the QoSinformation includes at least one QoS indicator value representingpriority and packet delay budget.
 7. The method of claim 1, wherein thedirect communication request message includes restriction informationrelated to the sidelink communication between the first apparatus andthe second apparatus.
 8. The method of claim 7, wherein the restrictioninformation includes information on transmission resources or receptionresources of the first apparatus.
 9. The method of claim 8, wherein,based on the information on transmission resources or receptionresources included in the restriction information, transmissionresources for the sidelink communication is selected by the secondapparatus.
 10. The method of claim 9, wherein the transmission resourcesselected by the second apparatus is different from the transmissionresources or the reception resources of the first apparatus.
 11. Themethod of claim 1, wherein the direct communication request messageincludes hybrid automatic repeat request (HARQ) capability of the firstapparatus.
 12. The method of claim 11, wherein the HARQ capability ofthe first apparatus includes at least one of whether the first apparatussupports sidelink HARQ feedback, whether the first apparatus supportsHARQ combining, or maximum number of the sidelink HARQ process supportedby the first apparatus.
 13. The method of claim 12, wherein, based onthe HARQ capability included in the direct communication requestmessage, transmission resources or retransmission resources for thesidelink communication is determined by the second apparatus.
 14. Afirst apparatus performing sidelink communication, the first apparatuscomprising: one or more memories storing instructions; one or moretransceivers; and one or more processors operably connected to the oneor more memories and the one or more transceivers, wherein the one ormore processors execute the instructions to: transmit, to a secondapparatus, a direct communication request message to establish unicastlink, which includes an identifier of the first apparatus andinformation regarding at least one service type, wherein the directcommunication request message further includes information regarding asecurity capability of the first apparatus, and wherein based on that anidentifier of the second apparatus is provided, the direct communicationrequest message further includes information regarding the identifier ofthe second apparatus; transmit, to the second apparatus, quality ofservice (QoS) information related to the at least one service type;receive, from the second apparatus, a direct communication acceptmessage including an identifier of the second apparatus and the QoSinformation related to the at least one service type; and perform thesidelink communication based on the unicast link between the firstapparatus and the second apparatus.
 15. An apparatus configured tocontrol a first user equipment (UE) to perform sidelink communication,the apparatus comprising: one or more processors; and one or morememories operably connected to the one or more processors and storinginstructions, wherein the one or more processors execute theinstructions to: transmit, to a second apparatus, a direct communicationrequest message to establish unicast link, which includes an identifierof the first apparatus and information related to at least one servicetype, wherein the direct communication request message further includesinformation regarding a security capability of the first apparatus, andwherein based on that an identifier of the second apparatus is provided,the direct communication request message further includes informationregarding the identifier of the second apparatus; transmit, to thesecond apparatus, quality of service (QoS) information related to the atleast one service type; receive, from the second apparatus, a directcommunication accept message including an identifier of the secondapparatus and the QoS information related to the at least one servicetype; and perform the sidelink communication based on the unicast linkbetween the first apparatus and the second apparatus.